GitHub Advisoryadvisory · npm

GHSA-8vch-m3f4-q8jf Elysia affected by arbitrary code injection through cookie config

HIGH Published 2025-12-09 Modified 2025-12-09 Official page ↗
Aliases
CVE-2025-66457
Ecosystem
npm
Packages
elysia
Severity
High
CVSS 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
Weaknesses
CWE-94
Reviewed
2025-12-09

Affected packages

• npm elysia: < 1.4.18 → fixed in 1.4.18

Description

Arbitrary code execution from cookie config. If dynamic cookies are enabled (ie there exists a schema for cookies), the cookie config is injected into the compiled route without first being sanitised. Availability of this exploit is generally low, as it 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). However when combined with GHSA-hxj9-33pp-j2cc, this vulnerability allows for a full RCE chain. Impact • aot enabled (default) • cookie schema passed to route • Cookie config controllable eg. via env Example of vulnerable code ```js new Elysia({ cookie: { secrets: `' + console.log('pwned from secrets') + '` }, }) .get("/", () => "hello world", { cookie: t.Cookie({ foo: t.Any(), }), }) ``` POC: https://github.com/sportshead/elysia-poc Patches Patched by 1.4.17 (https://github.com/elysiajs/elysia/pull/1564) Reference commit: • https://github.com/elysiajs/elysia/pull/1564/commits/26935bf76ebc43b4a43d48b173fc853de43bb51e • https://github.com/elysiajs/elysia/pull/1564/commits/3af978663e437dccc6c1a2a3aff4b74e1574849e Workarounds Sanitize cookie-related env input ```typescript const overrideUnsafeQuote = (value: string) => // '`' + value + '`' '`' + value.replace(/'/g, '\\`').replace(/\${/g, '$\\{') + '`' ```

Related

Alias · CVE (1)

  • CVE-2025-66457 Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation and client-server communication. vulnerability

Weakness · CWE (1)

  • CWE-94 Improper Control of Generation of Code weakness

References