tarfile.tar_filter could be bypassed using crafted link entries, including symlinks with empty or directory-like names, to redirect later archive members outside the intended extraction directory. This allowed a malicious tar archive to cause tarfile.extractall() with filter="tar" to write files outside the destination directory, subject to the permissions of the extracting process. This is the tarfile.tar_filter counterpart of CVE-2026-7774, which covered tarfile.data_filter.
https://mail.python.org/archives/list/[email protected]/thread/43JOWPRAV5DI3VZ4FUEUAZOHCATXXOCK/
https://github.com/python/cpython/pull/160098
https://github.com/python/cpython/issues/160097
https://github.com/python/cpython/commit/e7e0b3523ad6ba8472873dda594cf4021a16f8b5
https://github.com/python/cpython/commit/c6ada40177436e4e2533a7b252082b5f0c043477
https://github.com/python/cpython/commit/0901ad4ffb22605f12b705d1c1197f0a01f0ba0b
Published: 2026-10-22
Updated: 2026-10-23
Base Score: 6.4
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N
Severity: Medium
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Severity: High
Base Score: 6.9
Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Severity: Medium