CVE-2026-11940
tarfile extraction filter bypass allows escaping the destination directory
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.
How to fix CVE-2026-11940
No fixed version has been published yet. Mitigate by removing the affected package or applying upstream guidance from the references below.
- —no fix listed
- —no fix listed
- —no fix listed
Is CVE-2026-11940 being exploited?
Low — EPSS is 0.6%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
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CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | 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 |
References (9)
- WEBgithub.com/python/cpython/commit/27dd970bf6b17ebca7c8ed486a40ab043ed7af8f
- WEBgithub.com/python/cpython/commit/672825e2f36a57e173959b0d9d409d4560dab8df
- WEBgithub.com/python/cpython/commit/771d12dda5140313db0ac550292987975651bbde
- WEBgithub.com/python/cpython/commit/79c06bd5c6afa3c440d50faf7ee1b147c8832b4c