CVE-2026-11940
tarfile extraction filter bypass allows escaping the destination directory
- State
- Published
- Severity
- 7.8 High
- Published
- Jun 23, 2026
- Updated
- Aug 13, 2026
- Reserved
- Jun 10, 2026
Description
tarfile.extractall() with the 'data' or 'tar' filter could be bypassed by a crafted archive where a hardlink references a symlink stored at a deeper name than the hardlink itself. The extraction fallback validated the symlink at it's archived location but recreated it at the hardlink's shallower path, letting a relative target the filter judged contained escape the destination directory. This allowed a malicious tar archive to create a symlink pointing outside the destination, enabling out-of-destination file reads or writes. This was an incomplete fix of CVE-2025-4330.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 7.8 High | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N | PSF |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
CPythonPython Software Foundation |
|
References
- https://github.com/python/cpython/pull/151559patch
- https://mail.python.org/archives/list/security-announce@python.org/thread/LD6QIISNQFQYOIEPJNEUIPV7S3V76FZH/vendor-advisory
- https://github.com/python/cpython/issues/151558issue-tracking
- https://github.com/python/cpython/commit/27dd970bf6b17ebca7c8ed486a40ab043ed7af8fpatch
- https://github.com/python/cpython/commit/672825e2f36a57e173959b0d9d409d4560dab8dfpatch
- https://github.com/python/cpython/commit/771d12dda5140313db0ac550292987975651bbdepatch
- https://github.com/python/cpython/commit/79c06bd5c6afa3c440d50faf7ee1b147c8832b4cpatch
- https://github.com/python/cpython/commit/be13e86f6b9788a6f4d0419dffef72cbae5865c9patch
- https://github.com/python/cpython/commit/e5fdbd8d5aa923bd9111b112ea73bd6ec7c47877patch
- https://github.com/python/cpython/commit/0f852b3f07dd8e71e40326a51c02afbf16a42cc5patch
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