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Fix NUL bytes in UBJSON/BJData high-precision numbers #5760

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Merged
nlohmann merged 6 commits into from
Oct 6, 2026
Merged

Fix NUL bytes in UBJSON/BJData high-precision numbers #5760

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069783d
Fix NUL-terminated UBJSON and BJData high-precision payloads
fhgffy Oct 4, 2026
6cc848e
Use English comments for the high-precision NUL fix
fhgffy Oct 4, 2026
78d209f
Track NUL bytes while reading high-precision payloads
fhgffy Oct 4, 2026
9a16aa2
Drop dates from code comments.
fhgffy Oct 4, 2026
8588c55
Report a NUL in a high-precision number where it is read
fhgffy Oct 4, 2026
bdb821a
Use fixed text for the high-precision NUL error
fhgffy Oct 5, 2026
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6 changes: 6 additions & 0 deletions include/nlohmann/detail/input/binary_reader.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3249,6 +3249,12 @@ class binary_reader
{
return false;
}
// the lexer would stop at a NUL and accept the digits before it
if (JSON_HEDLEY_UNLIKELY(current == '\0'))
{
return sax->parse_error(chars_read, "00", parse_error::create(115, chars_read,
exception_message("invalid number text; last byte: 0x00", "high-precision number"), nullptr));
}
number_vector.push_back(static_cast<char>(current));
}

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6 changes: 6 additions & 0 deletions single_include/nlohmann/json.hpp
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Expand Up @@ -16966,6 +16966,12 @@ class binary_reader
{
return false;
}
// the lexer would stop at a NUL and accept the digits before it
if (JSON_HEDLEY_UNLIKELY(current == '\0'))
{
return sax->parse_error(chars_read, "00", parse_error::create(115, chars_read,
exception_message("invalid number text; last byte: 0x00", "high-precision number"), nullptr));
}
number_vector.push_back(static_cast<char>(current));
}

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26 changes: 26 additions & 0 deletions tests/src/unit-bjdata.cpp
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Expand Up @@ -1286,6 +1286,32 @@ TEST_CASE("BJData")
CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vec2), "[json.exception.parse_error.115] parse error at byte 5: syntax error while parsing BJData high-precision number: invalid number text: 1A", json::parse_error);
std::vector<uint8_t> const vec3 = {'H', 'i', 2, '1', '.'};
CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vec3), "[json.exception.parse_error.115] parse error at byte 5: syntax error while parsing BJData high-precision number: invalid number text: 1.", json::parse_error);
// Reject NULs where they are read, including trailing NULs and payloads cut off after one.
SECTION("NUL in high-precision number (issue #5753)")
{
for (const auto& vec : std::vector<std::vector<uint8_t>>
{
{'H', 'i', 3, '1', 0, 'x'},
{'H', 'i', 2, '1', 0},
{'H', 'i', 3, '1', 0}
})
{
CAPTURE(vec)
CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vec), "[json.exception.parse_error.115] parse error at byte 5: syntax error while parsing BJData high-precision number: invalid number text; last byte: 0x00", json::parse_error);
CHECK(json::from_bjdata(vec, true, false).is_discarded());
CHECK(json::from_bjdata(vec, false, false).is_discarded());
}

std::vector<uint8_t> const nested = {'[', 'H', 'i', 3, '1', 0, 'x', ']'};
CHECK_THROWS_WITH_AS(_ = json::from_bjdata(nested), "[json.exception.parse_error.115] parse error at byte 6: syntax error while parsing BJData high-precision number: invalid number text; last byte: 0x00", json::parse_error);
CHECK(json::from_bjdata(nested, true, false).is_discarded());

std::vector<uint8_t> const valid = {'H', 'i', 1, '1'};
const auto j = json::from_bjdata(valid);
CHECK(j.is_number_unsigned());
CHECK(j == json(1));
}

std::vector<uint8_t> const vec_overflow = {'H', 'i', 5, '1', 'e', '4', '0', '0'};
CHECK_THROWS_WITH_AS(_ = json::from_bjdata(vec_overflow), "[json.exception.out_of_range.406] number overflow parsing '1e400'", json::out_of_range);
std::vector<uint8_t> const vec4 = {'H', 2, '1', '0'};
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26 changes: 26 additions & 0 deletions tests/src/unit-ubjson.cpp
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Expand Up @@ -802,6 +802,32 @@ TEST_CASE("UBJSON")
CHECK_THROWS_WITH_AS(_ = json::from_ubjson(vec2), "[json.exception.parse_error.115] parse error at byte 5: syntax error while parsing UBJSON high-precision number: invalid number text: 1A", json::parse_error);
std::vector<uint8_t> const vec3 = {'H', 'i', 2, '1', '.'};
CHECK_THROWS_WITH_AS(_ = json::from_ubjson(vec3), "[json.exception.parse_error.115] parse error at byte 5: syntax error while parsing UBJSON high-precision number: invalid number text: 1.", json::parse_error);
// Reject NULs where they are read, including trailing NULs and payloads cut off after one.
SECTION("NUL in high-precision number (issue #5753)")
{
for (const auto& vec : std::vector<std::vector<uint8_t>>
{
{'H', 'i', 3, '1', 0, 'x'},
{'H', 'i', 2, '1', 0},
{'H', 'i', 3, '1', 0}
})
{
CAPTURE(vec)
CHECK_THROWS_WITH_AS(_ = json::from_ubjson(vec), "[json.exception.parse_error.115] parse error at byte 5: syntax error while parsing UBJSON high-precision number: invalid number text; last byte: 0x00", json::parse_error);
CHECK(json::from_ubjson(vec, true, false).is_discarded());
CHECK(json::from_ubjson(vec, false, false).is_discarded());
}

std::vector<uint8_t> const nested = {'[', 'H', 'i', 3, '1', 0, 'x', ']'};
CHECK_THROWS_WITH_AS(_ = json::from_ubjson(nested), "[json.exception.parse_error.115] parse error at byte 6: syntax error while parsing UBJSON high-precision number: invalid number text; last byte: 0x00", json::parse_error);
CHECK(json::from_ubjson(nested, true, false).is_discarded());

std::vector<uint8_t> const valid = {'H', 'i', 1, '1'};
const auto j = json::from_ubjson(valid);
CHECK(j.is_number_unsigned());
CHECK(j == json(1));
}

std::vector<uint8_t> const vec_overflow = {'H', 'i', 5, '1', 'e', '4', '0', '0'};
CHECK_THROWS_WITH_AS(_ = json::from_ubjson(vec_overflow), "[json.exception.out_of_range.406] number overflow parsing '1e400'", json::out_of_range&);
std::vector<uint8_t> const vec4 = {'H', 2, '1', '0'};
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