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.

melange QEMU runner could write files outside workspace directory