elysiajs elysia up to 1.4.17 code injection

Summaryinfo

A vulnerability identified as critical has been detected in elysiajs elysia up to 1.4.17. This affects an unknown function. The manipulation leads to code injection. This vulnerability is traded as CVE-2025-66457. It is possible to initiate the attack remotely. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in elysiajs elysia up to 1.4.17. It has been rated as critical. This issue affects some unknown functionality. The manipulation with an unknown input leads to a code injection vulnerability. Using CWE to declare the problem leads to CWE-94. The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2025-66457 since 12/01/2025. The exploitation is known to be easy. The attack may be initiated remotely. Additional levels of successful authentication are needed for exploitation. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1059 according to MITRE ATT&CK.

Upgrading to version 1.4.18 eliminates this vulnerability. Applying the patch 26935bf76ebc43b4a43d48b173fc853de43bb51e is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Vendor

• elysiajs

Name

• elysia

Version

• 1.4.0
• 1.4.1
• 1.4.2
• 1.4.3
• 1.4.4
• 1.4.5
• 1.4.6
• 1.4.7
• 1.4.8
• 1.4.9
• 1.4.10
• 1.4.11
• 1.4.12
• 1.4.13
• 1.4.14
• 1.4.15
• 1.4.16
• 1.4.17

License

• open-source

Website

• Product: https://github.com/elysiajs/elysia/

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