CVE-2025-8291: Vulnerability in Python Software Foundation CPython
CVE-2025-8291 is a medium severity vulnerability in the Python Software Foundation's CPython implementation affecting the 'zipfile' module. The issue arises because the module does not properly validate the offset value in the ZIP64 End of Central Directory (EOCD) Locator record and assumes the ZIP64 EOCD record is the previous record in the archive. This discrepancy can cause the 'zipfile' module to handle certain ZIP archives differently than other ZIP implementations. The remediation maintains the original behavior but adds a check to ensure the offset specified in the ZIP64 EOCD Locator record matches the expected value.
AI Analysis
Technical Summary
The vulnerability in CPython's 'zipfile' module involves improper validation of the ZIP64 EOCD Locator record offset. Instead of using the offset to locate the ZIP64 EOCD record, the module assumes it is the previous record in the ZIP archive. This can be exploited to craft ZIP archives that behave inconsistently when processed by the 'zipfile' module compared to other ZIP tools. The fix preserves the original behavior but adds validation to confirm the offset matches the expected location, mitigating potential abuse.
Potential Impact
This vulnerability could lead to inconsistent handling of ZIP64 archives by the 'zipfile' module, potentially causing unexpected behavior or logic errors in applications relying on it. There is no direct confidentiality, availability, or privilege escalation impact reported. The CVSS score of 4.3 (medium) reflects limited impact with no known exploits in the wild.
Mitigation Recommendations
No official patch links are provided in the data. The vendor's remediation approach is to maintain the existing behavior but add validation checks on the ZIP64 EOCD Locator offset. Users should monitor official Python Software Foundation advisories for updates or patches addressing this issue. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance.
CVE-2025-8291: Vulnerability in Python Software Foundation CPython
Description
CVE-2025-8291 is a medium severity vulnerability in the Python Software Foundation's CPython implementation affecting the 'zipfile' module. The issue arises because the module does not properly validate the offset value in the ZIP64 End of Central Directory (EOCD) Locator record and assumes the ZIP64 EOCD record is the previous record in the archive. This discrepancy can cause the 'zipfile' module to handle certain ZIP archives differently than other ZIP implementations. The remediation maintains the original behavior but adds a check to ensure the offset specified in the ZIP64 EOCD Locator record matches the expected value.
CVSS v3.1
Score 4.3medium
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in CPython's 'zipfile' module involves improper validation of the ZIP64 EOCD Locator record offset. Instead of using the offset to locate the ZIP64 EOCD record, the module assumes it is the previous record in the ZIP archive. This can be exploited to craft ZIP archives that behave inconsistently when processed by the 'zipfile' module compared to other ZIP tools. The fix preserves the original behavior but adds validation to confirm the offset matches the expected location, mitigating potential abuse.
Potential Impact
This vulnerability could lead to inconsistent handling of ZIP64 archives by the 'zipfile' module, potentially causing unexpected behavior or logic errors in applications relying on it. There is no direct confidentiality, availability, or privilege escalation impact reported. The CVSS score of 4.3 (medium) reflects limited impact with no known exploits in the wild.
Mitigation Recommendations
No official patch links are provided in the data. The vendor's remediation approach is to maintain the existing behavior but add validation checks on the ZIP64 EOCD Locator offset. Users should monitor official Python Software Foundation advisories for updates or patches addressing this issue. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance.
Technical Details
- Data Version
- 5.1
- Assigner Short Name
- PSF
- Date Reserved
- 2025-07-28T21:05:06.237Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 68e558f4a677756fc99b5208
Added to database: 10/07/2025, 18:16:20 UTC
Last enriched: 08/07/2026, 15:00:37 UTC
Last updated: 09/10/2026, 19:36:52 UTC
Views: 985
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