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GHSA-8vch-m3f4-q8jf

HighCVSS 7.5 / 10
Published Dec 9, 2025·Last modified Feb 4, 2026
Affected Components(0)

No affected components available

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

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

const overrideUnsafeQuote = (value: string) =>
	// '`' + value + '`'
	'`' + value.replace(/'/g, '\\`').replace(/\${/g, '$\\{') + '`'
Risk Scores
Base Score
7.5

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs high-level or administrative privileges. No user interaction is needed for the attacker to exploit this vulnerability.

Threat Intelligence
4.8

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
0.72%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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High severity
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