diff --git a/NuGet.config b/NuGet.config
index a61fb8523e1d8f..8d731f02bb5a1b 100644
--- a/NuGet.config
+++ b/NuGet.config
@@ -9,7 +9,7 @@
     <clear />
     <!--Begin: Package sources managed by Dependency Flow automation. Do not edit the sources below.-->
     <!--  Begin: Package sources from dotnet-emsdk -->
-    <add key="darc-pub-dotnet-emsdk-35ebe6f" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-emsdk-35ebe6f3/nuget/v3/index.json" />
+    <add key="darc-pub-dotnet-emsdk-ac9f809" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/darc-pub-dotnet-emsdk-ac9f8092/nuget/v3/index.json" />
     <!--  End: Package sources from dotnet-emsdk -->
     <!--  Begin: Package sources from dotnet-sdk -->
     <!--  End: Package sources from dotnet-sdk -->
diff --git a/eng/Version.Details.xml b/eng/Version.Details.xml
index 822c3cb1cc0fd8..ed12617c02e2c3 100644
--- a/eng/Version.Details.xml
+++ b/eng/Version.Details.xml
@@ -86,18 +86,18 @@
       <Sha>02fe27cd6a9b001c8feb7938e6ef4b3799745759</Sha>
       <SourceBuild RepoName="command-line-api" ManagedOnly="true" />
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Cecil" Version="0.11.4-alpha.26158.1">
+    <Dependency Name="Microsoft.DotNet.Cecil" Version="0.11.4-alpha.26281.3">
       <Uri>https://github.com/dotnet/cecil</Uri>
-      <Sha>dc12f3e6ccb3fd7b76c0d5ee3365e6b58d796de0</Sha>
+      <Sha>fca1a685c57d208f52fd7e7ba48e2059e3bf0c34</Sha>
       <SourceBuild RepoName="cecil" ManagedOnly="true" />
     </Dependency>
-    <Dependency Name="Microsoft.NET.Workload.Emscripten.Current.Manifest-8.0.100" Version="8.0.28">
+    <Dependency Name="Microsoft.NET.Workload.Emscripten.Current.Manifest-8.0.100" Version="8.0.29">
       <Uri>https://github.com/dotnet/emsdk</Uri>
-      <Sha>35ebe6f3e6953f878ed92f637ad8d7f27202f7a6</Sha>
+      <Sha>ac9f8092f4f527cb3ace4aac03f8d1dbadc39983</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.SourceBuild.Intermediate.emsdk" Version="8.0.28-servicing.26258.2">
+    <Dependency Name="Microsoft.SourceBuild.Intermediate.emsdk" Version="8.0.29-servicing.26303.5">
       <Uri>https://github.com/dotnet/emsdk</Uri>
-      <Sha>35ebe6f3e6953f878ed92f637ad8d7f27202f7a6</Sha>
+      <Sha>ac9f8092f4f527cb3ace4aac03f8d1dbadc39983</Sha>
       <SourceBuild RepoName="emsdk" ManagedOnly="true" />
     </Dependency>
     <Dependency Name="Microsoft.SourceBuild.Intermediate.source-build-assets" Version="8.0.0-alpha.1.26208.5">
@@ -112,9 +112,9 @@
     </Dependency>
   </ProductDependencies>
   <ToolsetDependencies>
-    <Dependency Name="Microsoft.DotNet.Arcade.Sdk" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.Arcade.Sdk" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
       <SourceBuild RepoName="arcade" ManagedOnly="true" />
     </Dependency>
     <Dependency Name="Microsoft.DotNet.XliffTasks" Version="1.0.0-beta.23475.1" CoherentParentDependency="Microsoft.DotNet.Arcade.Sdk">
@@ -122,69 +122,69 @@
       <Sha>73f0850939d96131c28cf6ea6ee5aacb4da0083a</Sha>
       <SourceBuild RepoName="xliff-tasks" ManagedOnly="true" />
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Helix.Sdk" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.Helix.Sdk" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.GenAPI" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.GenAPI" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.GenFacades" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.GenFacades" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.XUnitExtensions" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.XUnitExtensions" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.XUnitConsoleRunner" Version="2.5.1-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.XUnitConsoleRunner" Version="2.5.1-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Build.Tasks.Archives" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.Build.Tasks.Archives" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Build.Tasks.Packaging" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.Build.Tasks.Packaging" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Build.Tasks.Installers" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.Build.Tasks.Installers" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Build.Tasks.Templating" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.Build.Tasks.Templating" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Build.Tasks.Workloads" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.Build.Tasks.Workloads" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.CodeAnalysis" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.CodeAnalysis" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Build.Tasks.TargetFramework" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.Build.Tasks.TargetFramework" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.RemoteExecutor" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.RemoteExecutor" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.Build.Tasks.Feed" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.Build.Tasks.Feed" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.VersionTools.Tasks" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.VersionTools.Tasks" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.SharedFramework.Sdk" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.SharedFramework.Sdk" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
     <Dependency Name="System.ComponentModel.TypeConverter.TestData" Version="8.0.0-beta.26153.1">
       <Uri>https://github.com/dotnet/runtime-assets</Uri>
@@ -335,9 +335,9 @@
       <Uri>https://github.com/dotnet/xharness</Uri>
       <Sha>28f5ed3a089ff1a179f523da0c910348e9010414</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.DotNet.PackageTesting" Version="8.0.0-beta.26224.3">
+    <Dependency Name="Microsoft.DotNet.PackageTesting" Version="8.0.0-beta.26278.3">
       <Uri>https://github.com/dotnet/arcade</Uri>
-      <Sha>d9af20b993c474033098fe0851c2d71b4ecf434b</Sha>
+      <Sha>4b95fb1a9307265eb75f62d4937be50e6786e94e</Sha>
     </Dependency>
     <Dependency Name="optimization.windows_nt-x64.MIBC.Runtime" Version="1.0.0-prerelease.23566.3">
       <Uri>https://dev.azure.com/dnceng/internal/_git/dotnet-optimization</Uri>
diff --git a/eng/Versions.props b/eng/Versions.props
index 1429f85ac92bba..85be789a5832eb 100644
--- a/eng/Versions.props
+++ b/eng/Versions.props
@@ -1,11 +1,11 @@
 <Project>
   <PropertyGroup>
     <!-- The .NET product branding version -->
-    <ProductVersion>8.0.28</ProductVersion>
+    <ProductVersion>8.0.29</ProductVersion>
     <!-- File version numbers -->
     <MajorVersion>8</MajorVersion>
     <MinorVersion>0</MinorVersion>
-    <PatchVersion>28</PatchVersion>
+    <PatchVersion>29</PatchVersion>
     <SdkBandVersion>8.0.100</SdkBandVersion>
     <PackageVersionNet7>7.0.20</PackageVersionNet7>
     <PackageVersionNet6>6.0.36</PackageVersionNet6>
@@ -88,21 +88,21 @@
     <!-- SDK dependencies -->
     <MicrosoftDotNetApiCompatTaskVersion>8.0.100</MicrosoftDotNetApiCompatTaskVersion>
     <!-- Arcade dependencies -->
-    <MicrosoftDotNetBuildTasksFeedVersion>8.0.0-beta.26224.3</MicrosoftDotNetBuildTasksFeedVersion>
-    <MicrosoftDotNetCodeAnalysisVersion>8.0.0-beta.26224.3</MicrosoftDotNetCodeAnalysisVersion>
-    <MicrosoftDotNetGenAPIVersion>8.0.0-beta.26224.3</MicrosoftDotNetGenAPIVersion>
-    <MicrosoftDotNetGenFacadesVersion>8.0.0-beta.26224.3</MicrosoftDotNetGenFacadesVersion>
-    <MicrosoftDotNetXUnitExtensionsVersion>8.0.0-beta.26224.3</MicrosoftDotNetXUnitExtensionsVersion>
-    <MicrosoftDotNetXUnitConsoleRunnerVersion>2.5.1-beta.26224.3</MicrosoftDotNetXUnitConsoleRunnerVersion>
-    <MicrosoftDotNetBuildTasksArchivesVersion>8.0.0-beta.26224.3</MicrosoftDotNetBuildTasksArchivesVersion>
-    <MicrosoftDotNetBuildTasksInstallersVersion>8.0.0-beta.26224.3</MicrosoftDotNetBuildTasksInstallersVersion>
-    <MicrosoftDotNetBuildTasksPackagingVersion>8.0.0-beta.26224.3</MicrosoftDotNetBuildTasksPackagingVersion>
-    <MicrosoftDotNetBuildTasksTargetFrameworkVersion>8.0.0-beta.26224.3</MicrosoftDotNetBuildTasksTargetFrameworkVersion>
-    <MicrosoftDotNetBuildTasksTemplatingVersion>8.0.0-beta.26224.3</MicrosoftDotNetBuildTasksTemplatingVersion>
-    <MicrosoftDotNetBuildTasksWorkloadsPackageVersion>8.0.0-beta.26224.3</MicrosoftDotNetBuildTasksWorkloadsPackageVersion>
-    <MicrosoftDotNetRemoteExecutorVersion>8.0.0-beta.26224.3</MicrosoftDotNetRemoteExecutorVersion>
-    <MicrosoftDotNetVersionToolsTasksVersion>8.0.0-beta.26224.3</MicrosoftDotNetVersionToolsTasksVersion>
-    <MicrosoftDotNetPackageTestingVersion>8.0.0-beta.26224.3</MicrosoftDotNetPackageTestingVersion>
+    <MicrosoftDotNetBuildTasksFeedVersion>8.0.0-beta.26278.3</MicrosoftDotNetBuildTasksFeedVersion>
+    <MicrosoftDotNetCodeAnalysisVersion>8.0.0-beta.26278.3</MicrosoftDotNetCodeAnalysisVersion>
+    <MicrosoftDotNetGenAPIVersion>8.0.0-beta.26278.3</MicrosoftDotNetGenAPIVersion>
+    <MicrosoftDotNetGenFacadesVersion>8.0.0-beta.26278.3</MicrosoftDotNetGenFacadesVersion>
+    <MicrosoftDotNetXUnitExtensionsVersion>8.0.0-beta.26278.3</MicrosoftDotNetXUnitExtensionsVersion>
+    <MicrosoftDotNetXUnitConsoleRunnerVersion>2.5.1-beta.26278.3</MicrosoftDotNetXUnitConsoleRunnerVersion>
+    <MicrosoftDotNetBuildTasksArchivesVersion>8.0.0-beta.26278.3</MicrosoftDotNetBuildTasksArchivesVersion>
+    <MicrosoftDotNetBuildTasksInstallersVersion>8.0.0-beta.26278.3</MicrosoftDotNetBuildTasksInstallersVersion>
+    <MicrosoftDotNetBuildTasksPackagingVersion>8.0.0-beta.26278.3</MicrosoftDotNetBuildTasksPackagingVersion>
+    <MicrosoftDotNetBuildTasksTargetFrameworkVersion>8.0.0-beta.26278.3</MicrosoftDotNetBuildTasksTargetFrameworkVersion>
+    <MicrosoftDotNetBuildTasksTemplatingVersion>8.0.0-beta.26278.3</MicrosoftDotNetBuildTasksTemplatingVersion>
+    <MicrosoftDotNetBuildTasksWorkloadsPackageVersion>8.0.0-beta.26278.3</MicrosoftDotNetBuildTasksWorkloadsPackageVersion>
+    <MicrosoftDotNetRemoteExecutorVersion>8.0.0-beta.26278.3</MicrosoftDotNetRemoteExecutorVersion>
+    <MicrosoftDotNetVersionToolsTasksVersion>8.0.0-beta.26278.3</MicrosoftDotNetVersionToolsTasksVersion>
+    <MicrosoftDotNetPackageTestingVersion>8.0.0-beta.26278.3</MicrosoftDotNetPackageTestingVersion>
     <!-- NuGet dependencies -->
     <NuGetBuildTasksPackVersion>6.0.0-preview.1.102</NuGetBuildTasksPackVersion>
     <!-- Installer dependencies -->
@@ -227,7 +227,7 @@
     <!-- ILLink -->
     <MicrosoftNETILLinkTasksVersion>8.0.0-rc.1.23406.6</MicrosoftNETILLinkTasksVersion>
     <!-- Mono Cecil -->
-    <MicrosoftDotNetCecilVersion>0.11.4-alpha.26158.1</MicrosoftDotNetCecilVersion>
+    <MicrosoftDotNetCecilVersion>0.11.4-alpha.26281.3</MicrosoftDotNetCecilVersion>
     <!-- ILCompiler -->
     <MicrosoftDotNetILCompilerVersion>8.0.0-rc.1.23406.6</MicrosoftDotNetILCompilerVersion>
     <!-- ICU -->
@@ -253,7 +253,7 @@
          Note: when the name is updated, make sure to update dependency name in eng/pipelines/common/xplat-setup.yml
                like - DarcDependenciesChanged.Microsoft_NET_Workload_Emscripten_Current_Manifest-8_0_100_Transport
     -->
-    <MicrosoftNETWorkloadEmscriptenCurrentManifest80100Version>8.0.28</MicrosoftNETWorkloadEmscriptenCurrentManifest80100Version>
+    <MicrosoftNETWorkloadEmscriptenCurrentManifest80100Version>8.0.29</MicrosoftNETWorkloadEmscriptenCurrentManifest80100Version>
     <MicrosoftNETRuntimeEmscriptenVersion>$(MicrosoftNETWorkloadEmscriptenCurrentManifest80100Version)</MicrosoftNETRuntimeEmscriptenVersion>
     <!-- SdkVersionForWorkloadTesting is used to compute the sdk band and version for workload testing.
          The published manifests are built in dotnet/sdk so these values are for testing purposes only.
diff --git a/global.json b/global.json
index 8493e87c9f4890..06f51ca4fd3c7d 100644
--- a/global.json
+++ b/global.json
@@ -8,9 +8,9 @@
     "dotnet": "8.0.126"
   },
   "msbuild-sdks": {
-    "Microsoft.DotNet.Arcade.Sdk": "8.0.0-beta.26224.3",
-    "Microsoft.DotNet.Helix.Sdk": "8.0.0-beta.26224.3",
-    "Microsoft.DotNet.SharedFramework.Sdk": "8.0.0-beta.26224.3",
+    "Microsoft.DotNet.Arcade.Sdk": "8.0.0-beta.26278.3",
+    "Microsoft.DotNet.Helix.Sdk": "8.0.0-beta.26278.3",
+    "Microsoft.DotNet.SharedFramework.Sdk": "8.0.0-beta.26278.3",
     "Microsoft.Build.NoTargets": "3.7.0",
     "Microsoft.Build.Traversal": "3.4.0",
     "Microsoft.NET.Sdk.IL": "8.0.0-rc.1.23406.6"
diff --git a/src/coreclr/nativeaot/System.Private.CoreLib/src/Internal/Runtime/CompilerHelpers/InteropHelpers.cs b/src/coreclr/nativeaot/System.Private.CoreLib/src/Internal/Runtime/CompilerHelpers/InteropHelpers.cs
index faacce2ea5d14b..9761b2c9362ce1 100644
--- a/src/coreclr/nativeaot/System.Private.CoreLib/src/Internal/Runtime/CompilerHelpers/InteropHelpers.cs
+++ b/src/coreclr/nativeaot/System.Private.CoreLib/src/Internal/Runtime/CompilerHelpers/InteropHelpers.cs
@@ -45,7 +45,9 @@ internal static unsafe void StringToByValAnsiString(string str, byte* pNative, i
 
                 fixed (char* pManaged = str)
                 {
-                    PInvokeMarshal.StringToAnsiString(pManaged, lenUnicode, pNative, /*terminateWithNull=*/true, bestFit, throwOnUnmappableChar);
+                    PInvokeMarshal.StringToAnsiString(pManaged, lenUnicode, pNative,
+                        /*terminateWithNull=*/true, bestFit, throwOnUnmappableChar,
+                        nativeByteLength: charCount);
                 }
             }
             else
diff --git a/src/coreclr/nativeaot/System.Private.CoreLib/src/System/Runtime/InteropServices/PInvokeMarshal.cs b/src/coreclr/nativeaot/System.Private.CoreLib/src/System/Runtime/InteropServices/PInvokeMarshal.cs
index 61ed1dd6ec08d4..ef6c48c7bd5765 100644
--- a/src/coreclr/nativeaot/System.Private.CoreLib/src/System/Runtime/InteropServices/PInvokeMarshal.cs
+++ b/src/coreclr/nativeaot/System.Private.CoreLib/src/System/Runtime/InteropServices/PInvokeMarshal.cs
@@ -500,9 +500,14 @@ public static unsafe char AnsiCharToWideChar(byte nativeValue)
         }
 
         // c# string (UTF-16) to UTF-8 encoded byte array
+        // If specified, nativeByteLength represents the length of the output buffer and this function
+        // will not write more than that many bytes. If negative, this function writes as many bytes
+        // as needed to encode the string.
         internal static unsafe byte* StringToAnsiString(char* pManaged, int lenUnicode, byte* pNative, bool terminateWithNull,
-            bool bestFit, bool throwOnUnmappableChar)
+            bool bestFit, bool throwOnUnmappableChar, int nativeByteLength = -1)
         {
+            Debug.Assert(pNative != null || nativeByteLength == -1, "Native buffer should not be null when nativeByteLength is specified.");
+
             bool allAscii = Ascii.IsValid(new ReadOnlySpan<char>(pManaged, lenUnicode));
             int length;
 
@@ -515,6 +520,18 @@ public static unsafe char AnsiCharToWideChar(byte nativeValue)
                 length = GetByteCount(pManaged, lenUnicode);
             }
 
+            // Clamp to nativeByteLength when caller provides a bounded output buffer (ByValTStr).
+            // For non-ASCII, ConvertWideCharToMultiByte will throw (Unix) or truncate (Windows)
+            // when the encoded bytes exceed the clamped length. This matches CoreCLR behavior.
+            if (nativeByteLength >= 0)
+            {
+                int maxBytesToWrite = terminateWithNull ? Math.Max(0, nativeByteLength - 1) : nativeByteLength;
+                if (length > maxBytesToWrite)
+                {
+                    length = maxBytesToWrite;
+                }
+            }
+
             if (pNative == null)
             {
                 pNative = (byte*)Marshal.AllocCoTaskMem(checked(length + 1));
@@ -534,8 +551,8 @@ public static unsafe char AnsiCharToWideChar(byte nativeValue)
                                            throwOnUnmappableChar);
             }
 
-            // Zero terminate
-            if (terminateWithNull)
+            // Zero terminate if requested and the buffer is not specified to be size 0.
+            if (terminateWithNull && nativeByteLength != 0)
                 *(pNative + length) = 0;
 
             return pNative;
diff --git a/src/libraries/System.Formats.Tar/src/System/Formats/Tar/TarEntry.cs b/src/libraries/System.Formats.Tar/src/System/Formats/Tar/TarEntry.cs
index 4ae74325894d59..64eea60618b83b 100644
--- a/src/libraries/System.Formats.Tar/src/System/Formats/Tar/TarEntry.cs
+++ b/src/libraries/System.Formats.Tar/src/System/Formats/Tar/TarEntry.cs
@@ -336,7 +336,8 @@ internal Task ExtractRelativeToDirectoryAsync(string destinationDirectoryPath, b
             string? fileDestinationPath = GetFullDestinationPath(
                                                 destinationDirectoryPath,
                                                 Path.IsPathFullyQualified(name) ? name : Path.Join(destinationDirectoryPath, name));
-            if (fileDestinationPath == null)
+
+            if (fileDestinationPath is null || FilePathEscapesDirectory(destinationDirectoryPath, fileDestinationPath))
             {
                 throw new IOException(SR.Format(SR.TarExtractingResultsFileOutside, name, destinationDirectoryPath));
             }
@@ -357,7 +358,7 @@ internal Task ExtractRelativeToDirectoryAsync(string destinationDirectoryPath, b
                 string? linkDestination = GetFullDestinationPath(
                                             destinationDirectoryPath,
                                             Path.IsPathFullyQualified(linkName) ? linkName : Path.Join(Path.GetDirectoryName(fileDestinationPath), linkName));
-                if (linkDestination is null)
+                if (linkDestination is null || FilePathEscapesDirectory(destinationDirectoryPath, linkDestination))
                 {
                     throw new IOException(SR.Format(SR.TarExtractingResultsLinkOutside, linkName, destinationDirectoryPath));
                 }
@@ -372,7 +373,7 @@ internal Task ExtractRelativeToDirectoryAsync(string destinationDirectoryPath, b
                 string? linkDestination = GetFullDestinationPath(
                                             destinationDirectoryPath,
                                             Path.Join(destinationDirectoryPath, linkName));
-                if (linkDestination is null)
+                if (linkDestination is null || FilePathEscapesDirectory(destinationDirectoryPath, linkDestination))
                 {
                     throw new IOException(SR.Format(SR.TarExtractingResultsLinkOutside, linkName, destinationDirectoryPath));
                 }
@@ -383,6 +384,101 @@ internal Task ExtractRelativeToDirectoryAsync(string destinationDirectoryPath, b
             return (fileDestinationPath, linkTargetPath);
         }
 
+        // Check if the file destination path or the link target path escapes the destination directory, by walking through the relative path components and resolving symlinks at each step.
+        private static bool FilePathEscapesDirectory(string destinationDirectoryPath, string fileDestinationPath)
+        {
+            // Windows is case insensitive while Linux is case sensitive
+            // This ensures the comparison is consistent with how the OS would resolve the paths
+            StringComparison pathComparison = OperatingSystem.IsWindows()
+                ? StringComparison.OrdinalIgnoreCase
+                : StringComparison.Ordinal;
+
+            string resolvedDest = ResolvePhysicalPath(destinationDirectoryPath);
+            string destPrefix = resolvedDest.EndsWith(Path.DirectorySeparatorChar)
+                ? resolvedDest
+                : resolvedDest + Path.DirectorySeparatorChar;
+
+            // Normalize file path (resolves .. and . but not symlinks)
+            string normalizedFile = Path.GetFullPath(fileDestinationPath);
+
+            // Walk relative components, resolving symlinks at each step
+            string relative = normalizedFile.Substring(resolvedDest.Length)
+                .TrimStart(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar);
+
+            string[] components = relative.Split(new char[] { Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar },
+                StringSplitOptions.RemoveEmptyEntries);
+
+            string current = resolvedDest;
+
+            foreach (string component in components)
+            {
+                current = Path.Combine(current, component);
+
+                if (Path.Exists(current))
+                {
+                    string? resolved = ResolveSymlink(current);
+                    if (resolved is null)
+                    {
+                        return true;
+                    }
+                    current = resolved;
+                }
+
+                string normalizedCurrent = Path.GetFullPath(current);
+                if (!normalizedCurrent.StartsWith(destPrefix, pathComparison) &&
+                    !normalizedCurrent.Equals(resolvedDest, pathComparison))
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        private static string? ResolveSymlink(string path)
+        {
+            FileSystemInfo? target = new FileInfo(path).ResolveLinkTarget(returnFinalTarget: true);
+
+            if (target is null)
+            {
+                return Path.GetFullPath(path);
+            }
+
+            return target.FullName;
+        }
+
+        // Resolves the full path of the specified path, resolving symlinks at each step.
+        // This is needed to mitigate malicious entries in the archive that could lead to writing files outside of the intended directory.
+        private static string ResolvePhysicalPath(string path)
+        {
+            string fullPath = Path.GetFullPath(path);
+            string? root = Path.GetPathRoot(fullPath);
+
+            if (root is null)
+            {
+                return fullPath;
+            }
+
+            string[] components = fullPath.Substring(root.Length)
+                .Split(new char[] { Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar }, StringSplitOptions.RemoveEmptyEntries);
+            string current = root;
+            foreach (string component in components)
+            {
+                current = Path.Combine(current, component);
+                if (Path.Exists(current))
+                {
+                    string? resolved = ResolveSymlink(current);
+                    if (resolved is null)
+                    {
+                        return current;
+                    }
+                    current = resolved;
+                }
+            }
+
+            return current;
+        }
+
         // Returns the full destination path if the path is the destinationDirectory or a subpath. Otherwise, returns null.
         private static string? GetFullDestinationPath(string destinationDirectoryFullPath, string qualifiedPath)
         {
diff --git a/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectory.File.Tests.cs b/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectory.File.Tests.cs
index 9ffbcc00792703..4e8a5b8e89a811 100644
--- a/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectory.File.Tests.cs
+++ b/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectory.File.Tests.cs
@@ -3,6 +3,7 @@
 
 using System.IO;
 using System.Linq;
+using System.Text;
 using Xunit;
 
 namespace System.Formats.Tar.Tests
@@ -45,6 +46,7 @@ public void NonExistentDirectory_Throws()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public void SetsLastModifiedTimeOnExtractedFiles()
         {
             using TempDirectory root = new TempDirectory();
@@ -72,6 +74,7 @@ public void SetsLastModifiedTimeOnExtractedFiles()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public void SetsLastModifiedTimeOnExtractedDirectories()
         {
             using TempDirectory root = new TempDirectory();
@@ -208,6 +211,7 @@ public void Extract_AllSegmentsOfPath()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public void ExtractArchiveWithEntriesThatStartWithSlashDotPrefix()
         {
             using TempDirectory root = new TempDirectory();
@@ -233,6 +237,7 @@ public void ExtractArchiveWithEntriesThatStartWithSlashDotPrefix()
         [Theory]
         [InlineData(true)]
         [InlineData(false)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public void UnixFileModes(bool overwrite)
         {
             using TempDirectory source = new TempDirectory();
@@ -301,6 +306,7 @@ public void UnixFileModes(bool overwrite)
         [Theory]
         [InlineData(true)]
         [InlineData(false)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public void UnixFileModes_RestrictiveParentDir(bool overwrite)
         {
             using TempDirectory source = new TempDirectory();
@@ -341,6 +347,7 @@ public void UnixFileModes_RestrictiveParentDir(bool overwrite)
         }
 
         [ConditionalFact(typeof(MountHelper), nameof(MountHelper.CanCreateSymbolicLinks))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public void LinkBeforeTarget()
         {
             using TempDirectory source = new TempDirectory();
@@ -368,5 +375,96 @@ public void LinkBeforeTarget()
             Assert.True(File.Exists(filePath), $"{filePath}' does not exist.");
             Assert.True(File.Exists(linkPath), $"{linkPath}' does not exist.");
         }
+
+        [ConditionalFact(typeof(MountHelper), nameof(MountHelper.CanCreateSymbolicLinks))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
+        public void ExtractToDirectory_RejectsSymlinkDirectoryTraversal_WithNestedFile()
+        {
+            using TempDirectory root = new TempDirectory();
+            string destDir = Path.Combine(root.Path, "dest");
+            Directory.CreateDirectory(destDir);
+
+            // Absolute path outside destDir
+            string linkTarget = "/tmp/outside";
+
+            string tarPath = Path.Combine(root.Path, "symlink_dir_traversal.tar");
+            using (FileStream stream = new FileStream(tarPath, FileMode.Create, FileAccess.Write))
+            using (TarWriter writer = new TarWriter(stream, leaveOpen: false))
+            {
+                // symlink: "link" -> "/tmp/outside"
+                writer.WriteEntry(new PaxTarEntry(TarEntryType.SymbolicLink, "link")
+                {
+                    LinkName = linkTarget
+                });
+
+                // file: "link/test.txt" with "hello"
+                byte[] content = Encoding.UTF8.GetBytes("hello");
+                var fileEntry = new PaxTarEntry(TarEntryType.RegularFile, "link/test.txt")
+                {
+                    DataStream = new MemoryStream(content, writable: false)
+                };
+
+                fileEntry.DataStream.Position = 0;
+                writer.WriteEntry(fileEntry);
+            }
+
+            Assert.Throws<IOException>(() => TarFile.ExtractToDirectory(tarPath, destDir, overwriteFiles: true));
+
+            // Nothing should be created in dest
+            string linkPath = Path.Combine(destDir, "link");
+            string outsideFilePath = Path.Combine(destDir, "link", "test.txt");
+            Assert.False(File.Exists(linkPath) || Directory.Exists(linkPath), "link should not have been created.");
+            Assert.False(File.Exists(outsideFilePath) || Directory.Exists(linkPath), "traversal link should not have been created.");
+        }
+
+
+        [ConditionalFact(typeof(MountHelper), nameof(MountHelper.CanCreateSymbolicLinks))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX | TestPlatforms.Windows)]
+        public void ExtractToDirectory_RejectsChainedSymlinkDirectoryTraversal_WithNestedFile()
+        {
+            // dir a/
+            // symlink a/b → .
+            // symlink a/b/c → .
+            // symlink a/b/c/d → ../../outside
+            // file a/d/ pwned.txt escapes
+
+            using TempDirectory root = new TempDirectory();
+            string destDir = Path.Combine(root.Path, "dest");
+            Directory.CreateDirectory(destDir);
+
+            string tarPath = Path.Combine(root.Path, "chained_symlink_traversal.tar");
+            using (FileStream stream = new FileStream(tarPath, FileMode.Create, FileAccess.Write))
+            using (TarWriter writer = new TarWriter(stream, leaveOpen: false))
+            {
+                writer.WriteEntry(new PaxTarEntry(TarEntryType.Directory, "a/"));
+
+                writer.WriteEntry(new PaxTarEntry(TarEntryType.SymbolicLink, "a/b") { LinkName = "." });
+
+                writer.WriteEntry(new PaxTarEntry(TarEntryType.SymbolicLink, "a/b/c") { LinkName = "." });
+
+                writer.WriteEntry(new PaxTarEntry(TarEntryType.SymbolicLink, "a/b/c/d") { LinkName = "../../outside" });
+
+                var pwned = new PaxTarEntry(TarEntryType.RegularFile, "a/d/pwned.txt")
+                {
+                    DataStream = new MemoryStream(Encoding.UTF8.GetBytes("pwned"))
+                };
+                writer.WriteEntry(pwned);
+            }
+
+            if (OperatingSystem.IsWindows())
+            {
+                // Windows only creates file symlinks and trying to process a directory symlink will throw UnauthorizedAccessException instead of IOException
+                Assert.Throws<UnauthorizedAccessException>(() => TarFile.ExtractToDirectory(tarPath, destDir, overwriteFiles: true));
+            }
+            else
+            {
+                Assert.Throws<IOException>(() => TarFile.ExtractToDirectory(tarPath, destDir, overwriteFiles: true));
+            }
+
+            string outsideDir = Path.Combine(root.Path, "outside");
+            Assert.False(Directory.Exists(outsideDir), "outside/directory should not have been created.");
+            Assert.False(File.Exists(Path.Combine(outsideDir, "pwned.txt")), "pwned.txt should not have been written outside destination.");
+
+        }
     }
 }
diff --git a/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectory.Stream.Tests.cs b/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectory.Stream.Tests.cs
index 8bd60b6f3b4a53..03ec5658b0caa6 100644
--- a/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectory.Stream.Tests.cs
+++ b/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectory.Stream.Tests.cs
@@ -76,6 +76,7 @@ public void ExtractEntry_ManySubfolderSegments_NoPrecedingDirectoryEntries()
         [Theory]
         [InlineData(TarEntryType.SymbolicLink)]
         [InlineData(TarEntryType.HardLink)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public void Extract_LinkEntry_TargetOutsideDirectory(TarEntryType entryType)
         {
             using MemoryStream archive = new MemoryStream();
@@ -98,21 +99,25 @@ public void Extract_LinkEntry_TargetOutsideDirectory(TarEntryType entryType)
         [ConditionalTheory(typeof(MountHelper), nameof(MountHelper.CanCreateSymbolicLinks))]
         [InlineData(TarEntryFormat.Pax)]
         [InlineData(TarEntryFormat.Gnu)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public void Extract_SymbolicLinkEntry_TargetInsideDirectory(TarEntryFormat format) => Extract_LinkEntry_TargetInsideDirectory_Internal(TarEntryType.SymbolicLink, format, null);
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.SupportsHardLinkCreation))]
         [InlineData(TarEntryFormat.Pax)]
         [InlineData(TarEntryFormat.Gnu)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public void Extract_HardLinkEntry_TargetInsideDirectory(TarEntryFormat format) => Extract_LinkEntry_TargetInsideDirectory_Internal(TarEntryType.HardLink, format, null);
 
         [ConditionalTheory(typeof(MountHelper), nameof(MountHelper.CanCreateSymbolicLinks))]
         [InlineData(TarEntryFormat.Pax)]
         [InlineData(TarEntryFormat.Gnu)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public void Extract_SymbolicLinkEntry_TargetInsideDirectory_LongBaseDir(TarEntryFormat format) => Extract_LinkEntry_TargetInsideDirectory_Internal(TarEntryType.SymbolicLink, format, new string('a', 99));
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.SupportsHardLinkCreation))]
         [InlineData(TarEntryFormat.Pax)]
         [InlineData(TarEntryFormat.Gnu)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public void Extract_HardLinkEntry_TargetInsideDirectory_LongBaseDir(TarEntryFormat format) => Extract_LinkEntry_TargetInsideDirectory_Internal(TarEntryType.HardLink, format, new string('a', 99));
 
         // This test would not pass for the V7 and Ustar formats in some OSs like MacCatalyst, tvOSSimulator and OSX, because the TempDirectory gets created in
@@ -152,6 +157,7 @@ private void Extract_LinkEntry_TargetInsideDirectory_Internal(TarEntryType entry
         [InlineData(512)]
         [InlineData(512 + 1)]
         [InlineData(512 + 512 - 1)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public void Extract_UnseekableStream_BlockAlignmentPadding_DoesNotAffectNextEntries(int contentSize)
         {
             byte[] fileContents = new byte[contentSize];
@@ -208,6 +214,7 @@ public void PaxNameCollision_DedupInExtendedAttributes()
 
         [Theory]
         [MemberData(nameof(GetTestTarFormats))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public void UnseekableStreams_RoundTrip(TestTarFormat testFormat)
         {
             using TempDirectory root = new();
diff --git a/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectoryAsync.File.Tests.cs b/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectoryAsync.File.Tests.cs
index 42b0eef65eef87..efc8bbea35c5d9 100644
--- a/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectoryAsync.File.Tests.cs
+++ b/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectoryAsync.File.Tests.cs
@@ -57,6 +57,7 @@ public async Task NonExistentDirectory_Throws_Async()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public async Task SetsLastModifiedTimeOnExtractedFiles()
         {
             using TempDirectory root = new TempDirectory();
@@ -84,6 +85,7 @@ public async Task SetsLastModifiedTimeOnExtractedFiles()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public async Task SetsLastModifiedTimeOnExtractedDirectories()
         {
             using TempDirectory root = new TempDirectory();
@@ -236,6 +238,7 @@ public async Task Extract_AllSegmentsOfPath_Async()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public async Task ExtractArchiveWithEntriesThatStartWithSlashDotPrefix_Async()
         {
             using (TempDirectory root = new TempDirectory())
@@ -264,6 +267,7 @@ public async Task ExtractArchiveWithEntriesThatStartWithSlashDotPrefix_Async()
         [Theory]
         [InlineData(true)]
         [InlineData(false)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public async Task UnixFileModes_Async(bool overwrite)
         {
             using TempDirectory source = new TempDirectory();
@@ -330,6 +334,7 @@ public async Task UnixFileModes_Async(bool overwrite)
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public async Task UnixFileModes_RestrictiveParentDir_Async()
         {
             using TempDirectory source = new TempDirectory();
@@ -363,6 +368,7 @@ public async Task UnixFileModes_RestrictiveParentDir_Async()
         }
 
         [ConditionalFact(typeof(MountHelper), nameof(MountHelper.CanCreateSymbolicLinks))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public async Task LinkBeforeTargetAsync()
         {
             using TempDirectory source = new TempDirectory();
diff --git a/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectoryAsync.Stream.Tests.cs b/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectoryAsync.Stream.Tests.cs
index 4a163767e94043..3801481ca111d1 100644
--- a/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectoryAsync.Stream.Tests.cs
+++ b/src/libraries/System.Formats.Tar/tests/TarFile/TarFile.ExtractToDirectoryAsync.Stream.Tests.cs
@@ -136,6 +136,7 @@ public async Task ExtractEntry_PodmanImageTarWithRelativeSymlinksPointingInExtra
         [Theory]
         [InlineData(TarEntryType.SymbolicLink)]
         [InlineData(TarEntryType.HardLink)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public async Task Extract_LinkEntry_TargetOutsideDirectory_Async(TarEntryType entryType)
         {
             await using (MemoryStream archive = new MemoryStream())
@@ -160,21 +161,25 @@ public async Task Extract_LinkEntry_TargetOutsideDirectory_Async(TarEntryType en
         [ConditionalTheory(typeof(MountHelper), nameof(MountHelper.CanCreateSymbolicLinks))]
         [InlineData(TarEntryFormat.Pax)]
         [InlineData(TarEntryFormat.Gnu)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public Task Extract_SymbolicLinkEntry_TargetInsideDirectory_Async(TarEntryFormat format) => Extract_LinkEntry_TargetInsideDirectory_Internal_Async(TarEntryType.SymbolicLink, format, null);
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.SupportsHardLinkCreation))]
         [InlineData(TarEntryFormat.Pax)]
         [InlineData(TarEntryFormat.Gnu)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public Task Extract_HardLinkEntry_TargetInsideDirectory_Async(TarEntryFormat format) => Extract_LinkEntry_TargetInsideDirectory_Internal_Async(TarEntryType.HardLink, format, null);
 
         [ConditionalTheory(typeof(MountHelper), nameof(MountHelper.CanCreateSymbolicLinks))]
         [InlineData(TarEntryFormat.Pax)]
         [InlineData(TarEntryFormat.Gnu)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public Task Extract_SymbolicLinkEntry_TargetInsideDirectory_LongBaseDir_Async(TarEntryFormat format) => Extract_LinkEntry_TargetInsideDirectory_Internal_Async(TarEntryType.SymbolicLink, format, new string('a', 99));
 
         [ConditionalTheory(typeof(PlatformDetection), nameof(PlatformDetection.SupportsHardLinkCreation))]
         [InlineData(TarEntryFormat.Pax)]
         [InlineData(TarEntryFormat.Gnu)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public Task Extract_HardLinkEntry_TargetInsideDirectory_LongBaseDir_Async(TarEntryFormat format) => Extract_LinkEntry_TargetInsideDirectory_Internal_Async(TarEntryType.HardLink, format, new string('a', 99));
 
         // This test would not pass for the V7 and Ustar formats in some OSs like MacCatalyst, tvOSSimulator and OSX, because the TempDirectory gets created in
@@ -217,6 +222,7 @@ private async Task Extract_LinkEntry_TargetInsideDirectory_Internal_Async(TarEnt
         [InlineData(512)]
         [InlineData(512 + 1)]
         [InlineData(512 + 512 - 1)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public async Task Extract_UnseekableStream_BlockAlignmentPadding_DoesNotAffectNextEntries_Async(int contentSize)
         {
             byte[] fileContents = new byte[contentSize];
@@ -273,6 +279,7 @@ public async Task PaxNameCollision_DedupInExtendedAttributesAsync()
 
         [Theory]
         [MemberData(nameof(GetTestTarFormats))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129227", TestPlatforms.OSX)]
         public async Task UnseekableStreams_RoundTrip_Async(TestTarFormat testFormat)
         {
             using TempDirectory root = new();
diff --git a/src/libraries/System.Runtime.InteropServices/tests/System.Runtime.InteropServices.UnitTests/System/Runtime/InteropServices/Marshal/StructureToPtrTests.cs b/src/libraries/System.Runtime.InteropServices/tests/System.Runtime.InteropServices.UnitTests/System/Runtime/InteropServices/Marshal/StructureToPtrTests.cs
index 59cefc137cef81..f553f2945888a0 100644
--- a/src/libraries/System.Runtime.InteropServices/tests/System.Runtime.InteropServices.UnitTests/System/Runtime/InteropServices/Marshal/StructureToPtrTests.cs
+++ b/src/libraries/System.Runtime.InteropServices/tests/System.Runtime.InteropServices.UnitTests/System/Runtime/InteropServices/Marshal/StructureToPtrTests.cs
@@ -363,5 +363,59 @@ public struct InnerStruct
             public InnerStruct s;
             public byte b;
         }
+
+        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
+        public struct StructWithByValString
+        {
+            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 4)]
+            public string? Name;
+        }
+
+        [Fact]
+        [PlatformSpecific(TestPlatforms.AnyUnix)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/129228")]
+        public void StructureToPtr_ByValTStr_MultiByte_Overflow()
+        {
+            // ByValTStr uses UTF-8 on Unix. € is 3 bytes, so the string exceeds the specified SizeConst
+            var payload = new StructWithByValString { Name = "€€€" };
+
+            int size = Marshal.SizeOf<StructWithByValString>();
+            IntPtr buffer = Marshal.AllocHGlobal(size + 1);
+            byte sentinelValue = 0xFF;
+            try
+            {
+                Marshal.WriteByte(buffer, size, sentinelValue);
+                Assert.Throws<ArgumentException>(() => Marshal.StructureToPtr(payload, buffer, false));
+                Assert.Equal(sentinelValue, Marshal.ReadByte(buffer, size));
+            }
+            finally
+            {
+                Marshal.FreeHGlobal(buffer);
+            }
+        }
+
+        [Fact]
+        public void StructureToPtr_ByValTStr_Ascii_TruncatesLongString()
+        {
+            var payload = new StructWithByValString { Name = "abcdef" };
+
+            int size = Marshal.SizeOf<StructWithByValString>();
+            IntPtr buffer = Marshal.AllocHGlobal(size + 1);
+            byte sentinelValue = 0xFF;
+            try
+            {
+                Marshal.WriteByte(buffer, size, sentinelValue);
+                Marshal.StructureToPtr(payload, buffer, false);
+                Assert.Equal((byte)'a', Marshal.ReadByte(buffer, 0));
+                Assert.Equal((byte)'b', Marshal.ReadByte(buffer, 1));
+                Assert.Equal((byte)'c', Marshal.ReadByte(buffer, 2));
+                Assert.Equal((byte)0, Marshal.ReadByte(buffer, 3));
+                Assert.Equal(sentinelValue, Marshal.ReadByte(buffer, size));
+            }
+            finally
+            {
+                Marshal.FreeHGlobal(buffer);
+            }
+        }
     }
 }