Path Traversal in Wummel Patool
CVE-2026-29509
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.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (28.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 28.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Wummel Patool — versions 0
Weakness classification (CWE)
References
- github.com/wummel/patool/blob/main/doc/changelog.txt (release-notes)
- github.com/wummel/patool/releases/tag/4.0.5 (patch)
- www.vulncheck.com/advisories/patool-path-traversal-via-safe-extract-function (third-party-advisory)
Frequently asked questions
- What is CVE-2026-29509?
- CVE-2026-29509 is a medium-severity vulnerability in Wummel Patool, classified under Path Traversal. CVSS score: 5.4/10. Published 2026-06-26.
- How severe is CVE-2026-29509?
- Medium severity. CVSS v3 base score is 5.4 out of 10.