CVE-2026-41579: runc — Fix

Description

runc is a CLI tool for spawning and running containers according to the OCI specification. In versions prior to 1.3.6, 1.4.0-rc.1, 1.4.0-rc.12, 1.5.0-rc.1, and 1.5.0-rc.1, 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. This issue is not exploitable under Docker, because Docker creates a top-level read-only layer that masks any malicious /dev symlink present in the container image — unlike some other Linux container tooling, whose higher-level runtimes built on runc remain exposed to exploitation via a malicious image. This issue has been fixed in versions 1.3.6, 1.4.3 and 1.5.0.

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CVSS v3.1 Score

3.3

LOW

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

EPSS — Exploit Prediction

0.0019

Probability of exploitation

0.09%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-61 CWE-61

Affected Products

Vendor	Product	Versions
linuxfoundation	runc	< 1.3.6
linuxfoundation	runc	1.4.0 — 1.4.3
linuxfoundation	runc	All
linuxfoundation	runc	All

References

Advisories & Patches

https://github.com/opencontainers/runc/commit/864db8042dbb https://github.com/opencontainers/runc/security/advisories/GHSA-xjvp-4fhw-gc47

Frequently Asked Questions

What is CVE-2026-41579? +

runc is a CLI tool for spawning and running containers according to the OCI specification. In versions prior to 1.3.6, 1.4.0-rc.1, 1.4.0-rc.12, 1.5.0-rc.1, and 1.5.0-rc.1, 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. This issue is not exploitable under Docker, because Docker creates a top-level read-only layer that masks any malicious /dev symlink present in the container image — unlike some other Linux container tooling, whose higher-level runtimes built on runc remain exposed to exploitation via a malicious image. This issue has been fixed in versions 1.3.6, 1.4.3 and 1.5.0. It has a CVSS v3.1 base score of 3.3 (LOW).

How severe is CVE-2026-41579? +

CVE-2026-41579 has a CVSS v3.1 score of 3.3 out of 10, rated LOW. This is a low-severity vulnerability with limited impact. The EPSS score is 0.0019, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-41579? +

CVE-2026-41579 affects products from linuxfoundation, specifically: runc. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-41579? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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