CVE-2025-62161 is a critical (CVSS 10.0) container escape in youki, the container runtime written in Rust. Versions 0.5.6 and below validate the /dev/null source too weakly when masking files by bind mount. The record says it is fixed in 0.5.7, which is the version to move to.
What's affected
- Product: youki, a container runtime written in Rust (cargo package
youki). - Weaknesses: CWE-363 (race condition enabling link following) and CWE-61 (UNIX symbolic link following).
- Affected per the CVE record: versions 0.5.6 and below.
- Fixed: 0.5.7, per the record.
- CVSS 3.1 in the record: 10.0, vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.
Source conflict: the GitHub advisory lists affected versions as 0.5.5 and below and gives 0.5.5 as the patched version, which cannot both be right, and its mitigation section says TBD. It also rates the issue High 7.3 under CVSS 4.0 with a local attack vector and active user interaction, against the 10.0 network score in the CVE record. Use 0.5.7 or later and confirm against the project release notes.
How to check if you're exposed
Find the runtime version on every host that uses youki:
youki --version
cargo install --list | grep -i youki
Also check container platform configuration. youki is often installed as an alternative runtime for Docker, Podman or Kubernetes nodes, so look at your runtime configuration for a youki entry and which nodes run it.
Anything at 0.5.6 or lower is in scope. Then ask who can start containers. The advisory describes the attack as swapping /dev/null for a symbolic link in the window between validation and the mount, so the risk is highest where untrusted images or users can run containers: shared clusters, CI runners and build services.
What to do now
- Upgrade youki to 0.5.7 or later on every host and confirm with
youki --version. - Prioritize nodes that run untrusted or third-party images, and CI runners.
- Restart or reschedule workloads so they start under the new runtime.
- Read the related runc advisory referenced by the youki advisory, GHSA-9493-h29p-rfm2, if you also run runc.
- Limit who can launch containers and which images are allowed, using an admission policy or an allow list of registries.
- Scan the images and build pipelines with the free in-browser dependency scan to see which components depend on affected runtimes.
Why it matters
A container runtime builds the walls between a container and its host. One of those steps hides sensitive paths by bind mounting /dev/null over them. The advisory says youki did not confirm that the source it mounted was the real /dev/null, and left a gap between the check and the mount. If an attacker swaps in a symbolic link in that gap, a file from the host can be mounted into the container.
This is a time-of-check to time-of-use race, tied to symbolic link following. The project advisory says the core logic resembles an issue found in runc, and that the problem was confirmed in youki as well.
A container escape is serious because it breaks the main isolation assumption. The record scores confidentiality, integrity and availability as high with a changed scope. Remember the conflict in scores: the project itself rates it lower and as local, so how much urgency you apply depends on whether untrusted workloads run on your hosts. It is not marked as exploited in the wild, and not in the CISA KEV catalog.
Try it yourself
Click through it at your own pace, or open it full screen.
Quick check
Why do the scores differ?
The CVE record scores it 10.0 with a network vector. The project advisory scores it High 7.3 with a local vector and active user interaction. Treat the higher figure as a ceiling and patch.
Which youki version should I run?
Version 0.5.7 or later, per the CVE record. The advisory text has inconsistent version data, so confirm with the release notes.
Sources
- github.com/youki-dev/youki/security/advisories/GHSA-4g74-7cf (fetched)
- Safeguard Gold entry for CVE-2025-62161
- github.com/youki-dev/youki/commit/5886c91073b9be748bd8d5aed4 (listed in the CVE record, not fetched)
Last reviewed: 18 October 2026.
