CVE-2025-8291: Python Software Foundation CPython · CWE-1285
Affects Python Software Foundation CPythonSource GCVE Database
Not known to be exploited · CVSS 4.3 Medium.
Data as of 26 Oct 2026, 09:16 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 40% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 7 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Python Software Foundation CPython | Affected
| Fixed in– |
AI-suggested
A remediation has been implemented that maintains the original behavior but adds validation to ensure the ZIP64 EOCD Locator offset matches the expected value. No additional action is required beyond applying the official fix when available.
Description
The 'zipfile' module would not check the validity of the ZIP64 End of Central Directory (EOCD) Locator record offset value would not be used to locate the ZIP64 EOCD record, instead the ZIP64 EOCD record would be assumed to be the previous record in the ZIP archive. This could be abused to create ZIP archives that are handled differently by the 'zipfile' module compared to other ZIP implementations. Remediation maintains this behavior, but checks that the offset specified in the ZIP64 EOCD Locator record matches the expected value.
References
- github.com/python/cpython/pull/139702 (opens in a new tab)
- mail.python.org/archives/list/security-announce@python.org/thread/QECOPWMTH4VPPJAXAH2BGTA4XADOP62G/ (opens in a new tab)
- github.com/python/cpython/issues/139700 (opens in a new tab)
- github.com/python/cpython/commit/162997bb70e067668c039700141770687bc8f267 (opens in a new tab)
- github.com/python/cpython/commit/333d4a6f4967d3ace91492a39ededbcf3faa76a6 (opens in a new tab)
- github.com/python/cpython/commit/1d29afb0d6218aa8fb5e1e4a6133a4778d89bb46 (opens in a new tab)
- github.com/python/cpython/commit/76437ac248ad8ca44e9bf697b02b1e2241df2196 (opens in a new tab)
- github.com/python/cpython/commit/8392b2f0d35678407d9ce7d95655a5b77de161b4 (opens in a new tab)
- github.com/python/cpython/commit/bca11ae7d575d87ed93f5dd6a313be6246e3e388 (opens in a new tab)
- github.com/python/cpython/commit/d11e69d6203080e3ec450446bfed0516727b85c3 (opens in a new tab)
- github.com/psf/advisory-database/blob/main/advisories/python/PSF-2025-12.json (opens in a new tab)
- github.com/google/security-research/security/advisories/GHSA-hhv7-p4pg-wm6p (opens in a new tab)