CVE-2026-42574: apko dirFS has a symlink-following path traversal that allows multiple entry points to escape the build root

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-09 · updated 2026-07-24
Weakness: CWE-22

Description

apko allows users to build and publish OCI container images built from apk packages. From version 0.14.8 to before version 1.2.5, a crafted .apk could install a TypeSymlink tar entry whose target pointed outside the build root, and a subsequent directory-creation or file-write entry in the same or later archive could traverse that symlink to reach host paths the build user could write to. This issue has been patched in version 1.2.5.

Affected products

chainguard-dev apko: from 0.14.8, < 1.2.5

References

https://github.com/chainguard-dev/apko/commit/f5a96e1299ac81c7ea9441705ec467688086f442
https://github.com/chainguard-dev/apko/pull/2187
https://github.com/chainguard-dev/apko/releases/tag/v1.2.5
https://github.com/chainguard-dev/apko/security/advisories/GHSA-qq3r-w4hj-gjp6

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