CVE-2025-8291

ZIP64 End of Central Directory (EOCD) Locator record offset not checked

Published Oct 7, 2025 CVSS 3.1 · 4.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4354-1 pypy3 security update
Debian DLA Debian DLA DLA-4445-1 python3.9 security update
Ubuntu USN Ubuntu USN USN-7886-1 Python vulnerabilities
Ubuntu USN Ubuntu USN USN-7886-2 Python vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Weaknesses CWE-1285
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Python
Python cpython
Vendors & Products Python
Python cpython
Type Values Removed Values Added
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.
Title ZIP64 End of Central Directory (EOCD) Locator record offset not checked
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
PSF
Published
Updated
Jul 31, 2026, 2:01 PM
Reserved
Jul 28, 2025, 9:05 PM
Status
Deferred
Published
Oct 7, 2025, 6:16 PM
Modified
Oct 8, 2026, 10:10 PM
Severity
Moderate
Public date
Oct 7, 2025, 6:10 PM