runc: Malicious image with /dev symlink can trigger limited host filesystem integrity violations

Exploitation

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

CVSS 4.0

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

EPSS

• CVE-2026-41579: 0.19% estimated exploitation activity in the next 30 days; percentile 8.29 (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 When setting up the container rootfs, setupPtmx and setupDevSymlinks call os.Remove and os.Symlink with a filepath.Join string which allow an image with /dev as a symlink to trick runc into deleting files called ptmx on the host or creating a hardcoded set of symlinks with specific names and targets in an arbitrary pre-existing host directory. Please note that this issue is not exploitable under Docker because it creates a top-level ro layer that masks any malicious /dev symlink present in the container image (this is also done without mounting the lower layers so there is no opportunity for the malicious /dev symlink to trick it into resolving to some other path). Unfortunately, Podman and containerd<sup&dagger;</sup do not do this and so users using those higher-level runtimes with runc can be exploited via a malicious image. This issue mirrors a somewhat similar issue in crun, which was also published recently. &dagger; Actually, at the time the issue was analysed,…

Published by the source

22 Jun 2026, 20:01 UTC

Last modified by the source

22 Jun 2026, 20:01 UTC

Source last checked

26 Oct 2026, 15:24 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-xjvp-4fhw-gc47

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# Patch Next advisory brief: CVE-2026-41579

Advisory: runc: Malicious image with /dev symlink can trigger limited host filesystem integrity violations
IDs: CVE-2026-41579, GHSA-xjvp-4fhw-gc47
Record: https://patchnext.com/advisories/cve-2026-41579 (revision 1, source checked 26 Oct 2026, 15:24 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/opencontainers/runc 1.5.0-rc.3, 1.4.3, 1.3.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/opencontainers/runc: affected <= 1.3.5; >= 1.4.0, <= 1.4.2; >= 1.5.0-rc.1, <= 1.5.0-rc.2; fixed in 1.5.0-rc.3, 1.3.6, 1.4.3

## Suggested inspection (read-only)
- Go github.com/opencontainers/runc: 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 github.com/opencontainers/runc.
- 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-xjvp-4fhw-gc47 (GitHub-reviewed advisory GHSA-xjvp-4fhw-gc47 lists affected ranges: Go github.com/opencontainers/runc >=0 =1.4.0 =1.5.0-rc.1 <=1.5.0-rc.2)

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