tar filter allows writing outside destination via empty-named symlink

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.

Source published

22 Oct 2026 20:57:36 UTC

Source modified

23 Oct 2026 00:36:58 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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CVSS 4.0 · 6.9 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