CVE-2026-87910
mediumpriority · track · 0EPSS 0.005 · 42 %ileDEUSEPSS · scored 2026-10-22
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 1.9–5.7
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (18)
Products and version ranges known to be affected.
advisories (5)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-3335CPython: Schwachstelle ermöglicht Umgehen von SicherheitsvorkehrungenDeutsch2026-09-13csaf · cert_bundDE
Ein entfernter, authentisierter Angreifer kann eine Schwachstelle in CPython ausnutzen, um Sicherheitsvorkehrungen zu umgehen.
- BIT-libpython-2026-87910tarfile hardlink fallback ignores custom extraction filter rejection via None2026-09-17vendor · osvUS
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.
- BIT-python-2026-87910tarfile hardlink fallback ignores custom extraction filter rejection via None2026-09-17vendor · osvUS
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.
- BIT-python-min-2026-87910tarfile hardlink fallback ignores custom extraction filter rejection via None2026-09-17vendor · osvUS
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.
- PSF-2026-402026-09-11vendor · osvUS
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.
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (12) nvd
External citations — patches, advisories, analysis.
- http://www.openwall.com/lists/oss-security/2026/09/11/8
- https://github.com/python/cpython/commit/2eb0c2f1dc71847731b6ab30aebefd058d482a7f
- https://github.com/python/cpython/commit/3105a3498aaf681ce128cf5baf83c2e5574267c5
- https://github.com/python/cpython/commit/764fd0af8d9e19d3684a58d2e58bf770f0605036
- https://github.com/python/cpython/commit/9c17bace90f88dfba6d0e2fe23c8e7ae35f83955
- https://github.com/python/cpython/commit/a4919937a4e1e69a0d178909c6f20557eca5d1d0
- https://github.com/python/cpython/commit/c1f106d240c4ffcb3608ed0a20e8aba6c865f6d3
- https://github.com/python/cpython/commit/d9565e54b1fc6d63c5be9afd58114499128fa57b
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