chainguard-dev apko up to 1.1.0 pkg/apk/fs/rwosfs.go Join path traversal

Summaryinfo

A vulnerability, which was classified as critical, was found in chainguard-dev apko up to 1.1.0. This vulnerability affects the function Join of the file pkg/apk/fs/rwosfs.go. Such manipulation leads to path traversal. This vulnerability is uniquely identified as CVE-2026-25121. The attack can be launched remotely. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in chainguard-dev apko up to 1.1.0. It has been rated as critical. Affected by this issue is the function Join of the file pkg/apk/fs/rwosfs.go. The manipulation with an unknown input leads to a path traversal vulnerability. Using CWE to declare the problem leads to CWE-23. The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory. Impacted is integrity, and availability. CVE summarizes:

apko allows users to build and publish OCI container images built from apk packages. From version 0.14.8 to before 1.1.1, a path traversal vulnerability was discovered in apko's dirFS filesystem abstraction. An attacker who can supply a malicious APK package (e.g., via a compromised or typosquatted repository) could create directories or symlinks outside the intended installation root. The MkdirAll, Mkdir, and Symlink methods in pkg/apk/fs/rwosfs.go use filepath.Join() without validating that the resulting path stays within the base directory. This issue has been patched in version 1.1.1.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-25121 since 01/29/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1006 by the MITRE ATT&CK project.

Upgrading to version 1.1.1 eliminates this vulnerability. Applying the patch d8b7887a968a527791b3c591ae83928cb49a9f14 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• chainguard-dev

Name

• apko

Version

• 1.0
• 1.1.0

License

• open-source

Website

• Product: https://github.com/chainguard-dev/apko/

CPE 2.3info

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CPE 2.2info

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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