---
id: CVE-2025-8291
title: |-
  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 previo…
summary: |-
  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 previo…
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N'
cwe:
  - CWE-1285
published: '2025-10-07'
updated: '2026-07-30'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-8291'
references:
  - url: >-
      https://github.com/python/cpython/commit/162997bb70e067668c039700141770687bc8f267
    label: cna@python.org
  - url: >-
      https://github.com/python/cpython/commit/1d29afb0d6218aa8fb5e1e4a6133a4778d89bb46
    label: cna@python.org
  - url: >-
      https://github.com/python/cpython/commit/333d4a6f4967d3ace91492a39ededbcf3faa76a6
    label: cna@python.org
  - url: >-
      https://github.com/python/cpython/commit/76437ac248ad8ca44e9bf697b02b1e2241df2196
    label: cna@python.org
  - url: >-
      https://github.com/python/cpython/commit/8392b2f0d35678407d9ce7d95655a5b77de161b4
    label: cna@python.org
  - url: >-
      https://github.com/python/cpython/commit/bca11ae7d575d87ed93f5dd6a313be6246e3e388
    label: cna@python.org
  - url: >-
      https://github.com/python/cpython/commit/d11e69d6203080e3ec450446bfed0516727b85c3
    label: cna@python.org
  - url: 'https://github.com/python/cpython/issues/139700'
    label: cna@python.org
  - url: 'https://github.com/python/cpython/pull/139702'
    label: cna@python.org
  - url: >-
      https://mail.python.org/archives/list/security-announce@python.org/thread/QECOPWMTH4VPPJAXAH2BGTA4XADOP62G/
    label: cna@python.org
  - url: >-
      https://github.com/google/security-research/security/advisories/GHSA-hhv7-p4pg-wm6p
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: >-
      https://github.com/psf/advisory-database/blob/main/advisories/python/PSF-2025-12.json
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
epss: 0.00378
epssPercentile: 0.31696
ingestedAt: '2026-07-31T06:58:51.033Z'
---

## Overview

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

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.