If `shutil.unpack_archive()` is given a ZIP archive with an absolute Windows path containing a drive (`C:\\...`) then the archive will be extracted outside the target directory which is different than other operating systems. Only Windows is affected by this vulnerability.
https://github.com/python/cpython/pull/146591
https://github.com/python/cpython/issues/146581
https://github.com/python/cpython/commit/fc829e88753858c8ac669594bf0093f44948c0f4
https://github.com/python/cpython/commit/b01e594fbe754a960212f908d047294e880b52fd
https://github.com/python/cpython/commit/ab5ef98af693bded74a738570e81ea70abef2840
Published: 2026-04-27
Updated: 2026-05-13
Base Score: 7.8
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:C/A:N
Severity: High
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
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00046