{"id":"CVE-2025-66456","revision":"1ec711c8af6c4e21a374ab95f3b7c622","records":[{"revision":"1ec711c8af6c4e21a374ab95f3b7c622","observedAt":"2026-10-25T03:17:36.152+00:00","statement":{"source":"nvd","id":"CVE-2025-66456","aliases":[],"title":"Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation and client-server communication. Versions 1.4.0 through 1.4.16 contain a prototype pollution vulnerability in `mergeDeep` after merging results o…","description":"Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation and client-server communication. Versions 1.4.0 through 1.4.16 contain a 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. This issue is fixed in version 1.4.17. To workaround, remove the `__proto__ key` from body.","state":0,"publishedAt":"2025-12-09T20:15:54.76+00:00","modifiedAt":"2026-10-14T21:10:00.183+00:00","affected":[],"metrics":[{"system":"CVSS 4.0 · security-advisories@github.com · Secondary","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","score":9.1,"severity":"CRITICAL"},{"system":"CVSS 3.1 · nvd@nist.gov · Primary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://github.com/elysiajs/elysia/commit/26935bf76ebc43b4a43d48b173fc853de43bb51e","https://github.com/elysiajs/elysia/commit/3af978663e437dccc6c1a2a3aff4b74e1574849e","https://github.com/elysiajs/elysia/pull/1564","https://github.com/elysiajs/elysia/security/advisories/GHSA-8vch-m3f4-q8jf","https://github.com/elysiajs/elysia/security/advisories/GHSA-hxj9-33pp-j2cc"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-66456","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Analyzed","weaknesses":["CWE-1321"],"productCriteria":["cpe:2.3:a:elysiajs:elysia:*:*:*:*:*:node.js:*:*"],"sourceDates":{"published":"2025-12-09T20:15:54.760","lastModified":"2026-10-14T21:10:00.183"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2025-66456","identifiers":["CVE-2025-66456"]},"retained":false,"historicalAffected":[]}],"coverage":[]}