CVE-2026-87910
tarfile hardlink fallback ignores custom extraction filter rejection via None
CVSS Score
0.0
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-22 CWE-59 |
| Vendor | python software foundation |
| Product | cpython |
| Published | Sep 11, 2026 |
| Last Updated | Sep 12, 2026 |
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Affected Versions
Python Software Foundation / CPython
0 < 3.15.0
References
mail.python.org: https://mail.python.org/archives/list/[email protected]/thread/57TBTLL2W6APMZR3A25B2YV7GL3EPTDJ/ github.com: https://github.com/python/cpython/pull/157266 github.com: https://github.com/python/cpython/issues/157265 github.com: https://github.com/python/cpython/commit/d9565e54b1fc6d63c5be9afd58114499128fa57b github.com: https://github.com/python/cpython/commit/fb2f0bbc3b35264f09cc2cb2934b7987527a6bc2 openwall.com: http://www.openwall.com/lists/oss-security/2026/09/11/8
Credits
🔍 William Woodruff (https://github.com/woodruffw) Zanie Blue (https://github.com/zanieb) Petr Viktorin (https://github.com/encukou) Stan Ulbrych (https://github.com/StanFromIreland)