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Vulnerabilities

Security fix · 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, instea

Published Oct 7, 2025 · catalog updated Jul 31, 2026 · Python Software Foundation CPython

Last checked Oct 26, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-8291. EPSS is 0.47%. Act only if a listed version of Python Software Foundation CPython is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium4.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.47%
Remediation
Version ranges on file
Affected products
vendor Python Software Foundation CPython 3.10.0 <3.10.19

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor Python Software Foundation CPython 3.10.0 <3.10.193.10.0 <3.10.19

How to fix CVE-2025-8291

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-8291. EPSS is 0.47%. Act only if a listed version of Python Software Foundation CPython is installed.

Which versions are affected?

Compare what you have installed with Python Software Foundation CPython 3.10.0 <3.10.19 3.10.0 <3.10.19. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.47%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 7, 2025 · EUVD

    Detected

    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 implementation

  2. Jul 31, 2026 · EUVD

    Updated

    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 implementation

Sources

  • CVE.orgVulnerability recordCVE-2025-8291

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-8291

    30-day exploitation probability 0.47%

    first.org
  • EUVDVulnerability recordEUVD-2025-31917

    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

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 26, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 23, 2026
  • CVE.orgOct 22, 2026
  • EUVDOct 22, 2026