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.
Exploitability
AV:NAC:LAT:NPR:NUI:NVulnerable System
VC:NVI:NVA:NSubsequent System
SC:HSI:HSA:N7.8/CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:NFile System
Input Validation