When tarfile extracts a link on a system that doesn't support links, it falls back to extracting a member from the archive. In this case, the filter function is run twice: once for the extracted member, and once with name set to the location of the link. For one of the calls, the return value was ignored.
Instead, the member should be skipped if either call returns None.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
Low
Basic privileges needed
User Interaction
Active
User action required
Impact Assessment
Confidentiality
None
No data leak
Integrity
High
Complete data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
Vulnerable Products
python software foundation:cpython
References 6
https://github.com/python/cpython/issues/157265
cna@python.org
https://github.com/python/cpython/pull/157266
cna@python.org
https://mail.python.org/archives/list/security-announce@python.org/thread/57TBT…
cna@python.org
http://www.openwall.com/lists/oss-security/2026/09/11/8
af854a3a-2127-422b-91ae-364da2661108
https://github.com/python/cpython/commit/d9565e54b1fc6d63c5be9afd58114499128fa5…
NVD
https://github.com/python/cpython/commit/fb2f0bbc3b35264f09cc2cb2934b7987527a6b…
NVD