CVE-2026-87910
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network with a low-privilege account, but needs a user to act. High risk of data tampering.
- Exploit odds
- 0.6% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.6% in the next 30 days (EPSS).
- Severity: 5.7 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.6% · EPSS, next 30 days
- Weakness
- CWE-22 · Path traversal
- Record status
- Awaiting Analysis
Attack profile CVSS 4.0 · 5.7
- Attack vector
- Network
- Complexity
- Low
- Attack requirements
- Present
- Privileges needed
- Low
- User interaction
- Active
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Raw vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-87910.md and follow it. Check whether this project is affected by CVE-2026-87910. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- 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
- https://github.com/python/cpython/commit/fb2f0bbc3b35264f09cc2cb2934b7987527a6bc2
- https://github.com/python/cpython/pull/157266
References
- 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
- https://github.com/python/cpython/commit/fb2f0bbc3b35264f09cc2cb2934b7987527a6bc2
- https://github.com/python/cpython/issues/157265
- https://github.com/python/cpython/pull/157266
- https://mail.python.org/archives/list/[email protected]/thread/57TBTLL2W6APMZR3A25B2YV7GL3EPTDJ/
- http://www.openwall.com/lists/oss-security/2026/09/11/8