[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
devalue	5.1.1 -> 5.3.2

GitHub Vulnerability Alerts

CVE-2025-57820

1. devalue.parse allows __proto__ to be set

A string passed to devalue.parse could represent an object with a __proto__ property, which would assign a prototype to an object while allowing properties to be overwritten:

class Vector {
  constructor(x, y) {
    this.x = x;
    this.y = y;
  }

  get magnitude() {
    return (this.x ** 2 + this.y ** 2) ** 0.5;
  }
}

const payload = `[{"x":1,"y":2,"magnitude":3,"__proto__":4},3,4,"nope",["Vector",5],[6,7],8,9]`;

const vector = devalue.parse(payload, {
  Vector: ([x, y]) => new Vector(x, y)
});

console.log("Is vector", vector instanceof Vector); // true
console.log(vector.x) // 3
console.log(vector.y) // 4
console.log(vector.magnitude); // "nope" instead of 5

2. devalue.parse allows array prototype methods to be assigned to object

In a payload constructed with devalue.stringify, values are represented as array indices, where the array contains the 'hydrated' values:

devalue.stringify({ message: 'hello' }); // [{"message":1},"hello"]

devalue.parse does not check that an index is numeric, which means that it could assign an array prototype method to a property instead:

const object = devalue.parse('[{"toString":"push"}]');
object.toString(); // 0

This could be used by a creative attacker to bypass server-side validation.

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Release Notes

sveltejs/devalue (devalue)

v5.3.2

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Patch Changes

• 0623a47: fix: disallow array method access when parsing
• 0623a47: fix: disallow __proto__ properties on objects

v5.3.1

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Patch Changes

• ae904c5: fix: correctly differentiate between +0 and -0

v5.3.0

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Minor Changes

• 2896e7b: feat: support Temporal
• fec694d: feat: support URL and URLSearchParams objects

v5.2.0

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• Handle custom classes with null proto as pojo (#​95)

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