{"id":"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.","modified":"2026-10-01T15:30:05.275097480Z","published":"2026-10-01T15:13:23Z","database_specific":{"cwe_ids":["CWE-1321"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-10-01T15:13:23Z","nvd_published_at":null},"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"}],"affected":[{"package":{"name":"devalue","ecosystem":"npm","purl":"pkg:npm/devalue"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"5.9.3"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 5.9.2","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-4q55-j62x-fr9h/GHSA-4q55-j62x-fr9h.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N"}]}