youki container escape via "masked path" abuse due to mount race conditions

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

7.3 · CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H · score source

EPSS

• CVE-2025-62161: 0.26% estimated exploitation activity in the next 30 days; percentile 17.70 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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…

Published by the source

5 Nov 2025, 18:44 UTC

Last modified by the source

15 Nov 2025, 02:25 UTC

Source last checked

26 Oct 2026, 15:39 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-4g74-7cff-xcv8

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# Patch Next advisory brief: CVE-2025-62161

Advisory: youki container escape via "masked path" abuse due to mount race conditions
IDs: CVE-2025-62161, GHSA-4g74-7cff-xcv8
Record: https://patchnext.com/advisories/cve-2025-62161 (revision 1, source checked 26 Oct 2026, 15:39 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: youki 0.5.7. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io youki: affected < 0.5.7; fixed in 0.5.7

## Suggested inspection (read-only)
- crates.io youki: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on youki.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-4g74-7cff-xcv8 (GitHub-reviewed advisory GHSA-4g74-7cff-xcv8 lists affected ranges: crates.io youki >=0 <0.5.7)

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