melange QEMU runner could write files outside workspace directory

Open Source Vulnerabilities CVE-2026-24843

melange allows users to build apk packages using declarative pipelines. In version 0.11.3 to before 0.40.3, an attacker who can influence the tar stream from a QEMU guest VM could write files outside the intended workspace directory on the host. The retrieveWorkspace function extracts tar entries without validating that paths stay within the workspace, allowing path traversal via ../ sequences. This issue has been patched in version 0.40.3.

Open Source Vulnerabilities GO-2026-4407

melange QEMU runner could write files outside workspace directory in chainguard.dev/melange

Open Source Vulnerabilities GHSA-qxx2-7h4c-83f4

An attacker who can influence the tar stream from a QEMU guest VM could write files outside the intended workspace directory on the host. The `retrieveWorkspace` function extracts tar entries without validating that paths stay within the workspace, allowing Path Traversal via `../` sequences. **Fix:** Fixed in [6e243d0d](https://github.com/chainguard-dev/melange/commit/6e243d0d46699f837d7c392397a694d2bcc7612b). Merged in release. **Acknowledgements** melange thanks Oleh Konko from [1seal](https://1seal.org/) for discovering and reporting this issue.