Vulnerability · Published Dec 9, 2025 · Assigned by GitHub_M
CVE-2025-66457Elysia affected by arbitrary code injection through cookie config
High 7.5
In plain English
A high-severity code injection in elysia from elysiajs. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 57% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation and client-server communication. Versions 1.4.17 and below are subject to arbitrary code execution from cookie config. When dynamic cookies are enabled (e.g. there an existing cookie schema), the cookie config is injected into the compiled route without first being sanitised. Availability of this exploit is generally low, but when combined with GHSA-hxj9-33pp-j2cc, it allows for a full RCE chain. An attack requires write access to either the Elysia app's source code (in which case the vulnerability is meaningless) or write access to the cookie config (perhaps where it is assumed to be provisioned by the environment). This issue is fixed in version 1.4.18.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | elysia | 1.4.18 | GHSA-8vch-m3f4-q8jf |
Affected products (as reported)
Weakness: CWE-94 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
References
- https://github.com/elysiajs/elysia/security/advisories/GHSA-8vch-m3f4-q8jf x_refsource_CONFIRM
- https://github.com/elysiajs/elysia/security/advisories/GHSA-hxj9-33pp-j2cc x_refsource_MISC
- https://github.com/elysiajs/elysia/pull/1564 x_refsource_MISC
- https://github.com/elysiajs/elysia/commit/26935bf76ebc43b4a43d48b173fc853de43bb51e x_refsource_MISC
- https://github.com/elysiajs/elysia/commit/3af978663e437dccc6c1a2a3aff4b74e1574849e x_refsource_MISC
- https://github.com/sportshead/elysia-poc exploit