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Findings

CVE-2025-66457

Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation and client-server communication.

Published Dec 9, 2025 · updated Oct 14, 2026 · elysiajs elysia

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.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 9, 2025 · NIST NVD

    Detected

    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

  2. Oct 14, 2026 · NIST NVD

    Updated

    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

Affected

  • cpe elysiajs/elysiaversion unspecified

Sources

  • CVE.orgVulnerability recordCVE-2025-66457

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-66457

    30-day exploitation probability 0.8%

    first.org
  • NIST NVDVulnerability recordCVE-2025-66457

    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 s

    nvd.nist.gov

References