CVE-2025-66456: Elysia vulnerable to prototype pollution with multiple standalone schema validation
Prototype pollution vulnerability in mergeDeep after merging results of two standard schema validations with the same key. Due to the ordering of merging, there must be an any type that is set as a standalone guard, to allow for the __proto__ prop to be merged.
When combined with GHSA-8vch-m3f4-q8jf this allows for a full RCE by an attacker.
References
- github.com/advisories/GHSA-hxj9-33pp-j2cc
- github.com/elysiajs/elysia
- github.com/elysiajs/elysia/commit/26935bf76ebc43b4a43d48b173fc853de43bb51e
- github.com/elysiajs/elysia/commit/3af978663e437dccc6c1a2a3aff4b74e1574849e
- github.com/elysiajs/elysia/pull/1564
- github.com/elysiajs/elysia/security/advisories/GHSA-8vch-m3f4-q8jf
- github.com/elysiajs/elysia/security/advisories/GHSA-hxj9-33pp-j2cc
- github.com/sportshead/elysia-poc
- nvd.nist.gov/vuln/detail/CVE-2025-66456
Code Behaviors & Features
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