CVE-2025-8291
CVE-2025-8291 is a medium-severity vulnerability with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1285.
Key facts
- Severity: Medium (CVSS 3.x base score 4.3)
- EPSS exploit prediction: 0% (27th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2025-31917
- Weakness: CWE-1285
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2025-8291?
- 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.
- How severe is CVE-2025-8291?
- CVE-2025-8291 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
- Is CVE-2025-8291 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2025-8291?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2025-8291 have an EU (EUVD) identifier?
- Yes. CVE-2025-8291 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-31917.
- When was CVE-2025-8291 published?
- CVE-2025-8291 was published on 2025-10-07 and last updated on 2026-06-17.
References
- https://github.com/python/cpython/commit/162997bb70e067668c039700141770687bc8f267
- https://github.com/python/cpython/commit/1d29afb0d6218aa8fb5e1e4a6133a4778d89bb46
- https://github.com/python/cpython/commit/333d4a6f4967d3ace91492a39ededbcf3faa76a6
- https://github.com/python/cpython/commit/76437ac248ad8ca44e9bf697b02b1e2241df2196
- https://github.com/python/cpython/commit/8392b2f0d35678407d9ce7d95655a5b77de161b4
- https://github.com/python/cpython/commit/bca11ae7d575d87ed93f5dd6a313be6246e3e388
- https://github.com/python/cpython/commit/d11e69d6203080e3ec450446bfed0516727b85c3
- https://github.com/python/cpython/issues/139700
- https://github.com/python/cpython/pull/139702
- https://mail.python.org/archives/list/[email protected]/thread/QECOPWMTH4VPPJAXAH2BGTA4XADOP62G/
- https://github.com/google/security-research/security/advisories/GHSA-hhv7-p4pg-wm6p
- https://github.com/psf/advisory-database/blob/main/advisories/python/PSF-2025-12.json
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