CVE-2026-29509

Weakness

Patool before 4.0.5 contains a path traversal vulnerability in the safe_extract() function in patoolib/programs/py_tarfile.py when running on Python before 3.12, where the is_within_directory() helper uses os.path.commonprefix() for character-level string comparison instead of path-level comparison, allowing a crafted archive member path to bypass the containment check. Attackers can supply a malicious archive with specially crafted member paths to write arbitrary files.

References

• https://github.com/wummel/patool/blob/main/doc/changelog.txt
• https://github.com/wummel/patool/releases/tag/4.0.5
• https://www.vulncheck.com/advisories/patool-path-traversal-via-safe-extract-function