GHSA-4g74-7cff-xcv8 is a critical-severity (CVSS 10) CWE-61 vulnerability in youki. A fix is available for youki — see the affected versions and patch details below.
youki container escape via "masked path" abuse due to mount race conditions
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-4g74-7cff-xcv8.
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.
How urgent is this, really
GHSA-4g74-7cff-xcv8 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
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 utilizes bind mounting the container's /dev/null as a file mask. When performing this operation, the initial validation of the source /dev/null was insufficient. Specifically, we initially failed to verify whether /dev/null was genuinely present. However, we did perform validation to ensure that the /dev/null path existed within the container, including checking for symbolic links. Additionally, there was a vulnerability in the timing between validation and the actual mount operation.
As a result, by replacing /dev/null with a symbolic link, we can bind-mount arbitrary files from the host system.
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-9493-h29p-rfm2
Credits
Thanks to Lei Wang (@ssst0n3 from Huawei) for finding and reporting the original runc's vulnerability (Attack 1), and Li Fubang (@lifubang from acmcoder.com, CIIC) for discovering another attack vector in runc (Attack 2) based on @ssst0n3's initial findings.
Also, @cyphar helped youki in finding the problem.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | youki | all versions | 0.5.7cargo update -p youki --precise 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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update youki to 0.5.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4g74-7cff-xcv8 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-4g74-7cff-xcv8 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-4g74-7cff-xcv8. 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-4g74-7cff-xcv8 in your dependencies?
O3 Security finds GHSA-4g74-7cff-xcv8 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.