CVE-2026-11940
tarfile extraction filter bypass allows escaping the destination directory
- Published
- Updated
- Reserved
- Assigned by
- PSF
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
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| PSFCNA (assigner) | 4.0 | High7.8 | 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 |
| NVDNVD · Awaiting Analysis | 4.0 | High7.8 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.75% · top 45% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Weakness
Affected products
Python Software Foundation · CPython
- affected < 3.10.21
- affected 3.11.0 – < 3.11.16
- affected 3.12.0 – < 3.12.14
- affected 3.13.0 – < 3.13.15
- affected 3.14.0 – < 3.14.7
- affected 3.15.0a1 – < 3.15.0b4
References (10)
- https://github.com/python/cpython/pull/151559 (opens in a new tab)patch
- https://mail.python.org/archives/list/[email protected]/thread/LD6QIISNQFQYOIEPJNEUIPV7S3V76FZH/ (opens in a new tab)vendor-advisory
- https://github.com/python/cpython/issues/151558 (opens in a new tab)issue-tracking
- https://github.com/python/cpython/commit/27dd970bf6b17ebca7c8ed486a40ab043ed7af8f (opens in a new tab)patch
- https://github.com/python/cpython/commit/672825e2f36a57e173959b0d9d409d4560dab8df (opens in a new tab)patch
- https://github.com/python/cpython/commit/771d12dda5140313db0ac550292987975651bbde (opens in a new tab)patch
- https://github.com/python/cpython/commit/79c06bd5c6afa3c440d50faf7ee1b147c8832b4c (opens in a new tab)patch
- https://github.com/python/cpython/commit/be13e86f6b9788a6f4d0419dffef72cbae5865c9 (opens in a new tab)patch
- https://github.com/python/cpython/commit/e5fdbd8d5aa923bd9111b112ea73bd6ec7c47877 (opens in a new tab)patch
- https://github.com/python/cpython/commit/0f852b3f07dd8e71e40326a51c02afbf16a42cc5 (opens in a new tab)patch
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-11940)Record last updated .