GHSA-vf95-55w6-qmrf
CRITICALyouki container escape and denial of service due to arbitrary write gadgets and procfs write redirects
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
youkiReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
Impact
youki’s apparmor handling performs insufficiently strict write-target validation, which—combined with path substitution during pathname resolution—can allow writes to unintended procfs locations.
Weak write-target check
youki only verifies that the destination lies somewhere under procfs. As a result, a write intended for /proc/self/attr/apparmor/exec can succeed even if the path has been redirected to /proc/sys/kernel/hostname(which is also in procfs).
Path substitution While resolving a path component-by-component, a shared-mount race can substitute intermediate components and redirect the final target.
This is a different project, but the core logic is similar to the CVE in runc. Issues were identified in runc, and verification was also conducted in youki to confirm the problems. https://github.com/opencontainers/runc/security/advisories/GHSA-cgrx-mc8f-2prm
Credits
Thanks to Li Fubang (@lifubang from acmcoder.com, CIIC) and Tõnis Tiigi (@tonistiigi from Docker) for both independently discovering runc's original vulnerability, as well as Aleksa Sarai (@cyphar from SUSE) for the original research into this class of security issues and solutions.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | youki | all versions | 0.5.7 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for youki. 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 youki to 0.5.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-vf95-55w6-qmrf 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-vf95-55w6-qmrf 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-vf95-55w6-qmrf. 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-vf95-55w6-qmrf in your dependencies?
O3 detects GHSA-vf95-55w6-qmrf across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.