GHSA-2jfj-6hjv-fm6j
MEDIUMGHSA-2jfj-6hjv-fm6j is a medium-severity (CVSS 6.5) Information Exposure vulnerability. O3 Security confirms whether GHSA-2jfj-6hjv-fm6j is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
undici vulnerable to cross-user cookie disclosure via Set-Cookie caching in shared caches
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-2jfj-6hjv-fm6j.
Description
undici's cache interceptor does not handle the Set-Cookie response header anywhere in its cache path, so it neither refuses to store nor strips that header. In shared cache mode, which is the default, an otherwise cacheable response that carries a Set-Cookie header, for example one marked with a public and max-age directive, is stored and then re-served to a later caller that matches the same cache key. As a result one caller's cookie is disclosed to a different caller, and an untrusted server can inject cookies into cached responses served to all subsequent callers. This violates the requirement that a shared cache must not store cookies. This affects undici versions from 7.0.0 up to 7.29.1 and from 8.0.0 up to 8.10.2. Users should upgrade to undici 7.29.1 or 8.10.2.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. 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.
Remediation status
No patched version of the affected component has shipped for GHSA-2jfj-6hjv-fm6j yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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-2jfj-6hjv-fm6j 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-2jfj-6hjv-fm6j. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This flaw affects applications that use undici's shared-cache interceptor (interceptors.cache(), type: 'shared', which is the default) against untrusted or multi-tenant upstream servers. In that configuration, undici stores and re-serves the Set-Cookie header of cached responses, allowing one user's session cookie to…
Frequently Asked Questions
Is GHSA-2jfj-6hjv-fm6j in your dependencies?
O3 detects GHSA-2jfj-6hjv-fm6j across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.