GHSA-8vch-m3f4-q8jf
Elysia affected by arbitrary code injection through cookie config
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
elysiaReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
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, '$\\{') + '`'
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | elysia | all versions | 1.4.18 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for elysia. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update elysia to 1.4.18 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-8vch-m3f4-q8jf is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-8vch-m3f4-q8jf is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-8vch-m3f4-q8jf. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-8vch-m3f4-q8jf in your dependencies?
O3 detects GHSA-8vch-m3f4-q8jf across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.