Published Jun 12, 2025Sources checked Nov 12, 2026
7.5HIGHCVSS out of 10
What this means
Review the available evidence
CVE-2025-6021 and is rated High severity with a CVSS score of 7.5. 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: Aug 13, 2026
CBL-Mariner Releases
Vendor-listed releases
2.10.4-8
2.11.5-6
CISA KEVNot listedBased on the latest collected catalog
EPSS1.5%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2025-6021?
A flaw was found in libxml2's xmlBuildQName function, where integer overflows in buffer size calculations can lead to a stack-based buffer overflow. This issue can result in memory corruption or a denial of service when processing crafted input.