{"id":"GHSA-4q55-j62x-fr9h","aliases":[],"url":"https://o3.security/vulnerability/GHSA-4q55-j62x-fr9h","summary":"devalue: Malformed null-prototype object keys bypass __proto__ rejection via property-key coercion","details":"This is another instance of https://github.com/sveltejs/devalue/security/advisories/GHSA-mwv9-gp5h-frr4, where some payloads could cause `parse` to create objects with a `__proto__` own property. This on its own is not enough to cause prototype pollution, and indeed this is actually how `JSON.parse` works, but we decided to be a little more defensive here and not allow the creation of objects with `__proto__` own-properties. It is very unlikely for this to cause any issues.","published":"2026-10-01T15:13:23Z","modified":"2026-10-01T15:30:05.275097480Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"npm","name":"devalue","fixedVersion":"5.9.3"}],"fix":{"url":"https://github.com/sveltejs/devalue/commit/9ec513072e31f45e60d44dad6f0dba9c92bb8675","label":"sveltejs/devalue@9ec5130"},"references":[{"type":"WEB","url":"https://github.com/sveltejs/devalue/security/advisories/GHSA-4q55-j62x-fr9h"},{"type":"WEB","url":"https://github.com/sveltejs/devalue/commit/9ec513072e31f45e60d44dad6f0dba9c92bb8675"},{"type":"PACKAGE","url":"https://github.com/sveltejs/devalue"},{"type":"WEB","url":"https://github.com/sveltejs/devalue/releases/tag/v5.9.3"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-01T15:30:05.275097480Z"}}