Bug 2491848 (CVE-2026-11940) - CVE-2026-11940 python: cpython: CPython: tarfile extraction filter bypass allows escaping the destination directory
Summary: CVE-2026-11940 python: cpython: CPython: tarfile extraction filter bypass all...
Keywords:
Status: NEW
Alias: CVE-2026-11940
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2506027 2506028 2506029
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-06-23 17:05 UTC by OSIDB Bzimport
Modified: 2026-08-14 00:38 UTC (History)
28 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2026:54536 0 None None None 2026-08-13 11:25:54 UTC
Red Hat Product Errata RHBA-2026:54596 0 None None None 2026-08-13 15:01:05 UTC
Red Hat Product Errata RHBA-2026:54818 0 None None None 2026-08-14 00:38:31 UTC
Red Hat Product Errata RHSA-2026:54268 0 None None None 2026-08-12 11:03:40 UTC

Description OSIDB Bzimport 2026-06-23 17:05:56 UTC
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.

Comment 4 errata-xmlrpc 2026-08-12 11:03:38 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:54268 https://access.redhat.com/errata/RHSA-2026:54268


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