CVE intelligence

CVE-2025-8291

Vulnerability intelligence

Published Oct 7, 2025Sources checked Oct 25, 2026

4.3MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2025-8291 and is rated Medium severity with a CVSS score of 4.3. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Oct 23, 2026

Release Notes CBL-Mariner Releases

Vendor-listed releases

3.12.9-5
3.9.19-16

CISA KEVNot listedBased on the latest collected catalog

EPSS0.5%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

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.

Source: NVD