SB2026100109 - Path traversal in cpython

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Main Vulnerability Database SB2026100109

SB2026100109 - Path traversal in cpython

Published: October 1, 2026

Security Bulletin ID SB2026100109
CSH Severity
High
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

High 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Path traversal (CVE-ID: CVE-2026-11940)

CWE-ID: CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSSv4: 7.8 [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]


The vulnerability allows a remote attacker to perform directory traversal attacks.

The vulnerability exists due to 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. A remote attacker can use malicious tar archive to create a symlink pointing outside the destination, enabling out-of-destination file reads or writes.


Remediation

Install update from vendor's website.

References