CVE-2025-27612 is a medium-severity (CVSS 5.9) Incorrect Default Permissions vulnerability in libcontainer. A fix is available for libcontainer — see the affected versions and patch details below.
Libcontainer is affected by capabilities elevation
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 CVE-2025-27612.
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
CVE-2025-27612 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
libcontainerReal-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
In libcontainer, while creating a tenant container, the tenant builder accepts a list of capabilities to be added in the spec of tenant container. Code can be seen here . The logic here adds the given capabilities to all capabilities of main container if present in spec, otherwise simply set provided capabilities as capabilities of the tenant container.
However, GHSA-f3fp-gc8g-vw66 was opened on runc mentioning that setting inherited caps in any case for tenant container can lead to elevation of capabilities. For this, they added a fix here where they never set new inherited caps on tenant, and set ambient caps only if original container had inherited caps.
Similarly crun never sets inherited caps as can be seen here.
[!NOTE] This does not affect youki binary itself, as the exec implementation is partially broken and does not pass on the user-provided caps to tenant containers, this is only applicable if you are using libcontainer directly and using the tenant builder.
Workarounds
- Do not pass any user-provided capabilities to the tenant builder, in which case no capabilities will be set on tenant.
- Alternatively you can verify the capabilities of original container and filter the user passed capabilities before setting them on tenant.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | libcontainer | all versions | 0.5.3cargo update -p libcontainer --precise 0.5.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for libcontainer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update libcontainer to 0.5.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-27612 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 CVE-2025-27612 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-27612. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-27612 in your dependencies?
O3 Security finds CVE-2025-27612 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.