Published Jun 21, 2026Sources checked Nov 10, 2026
6.5MEDIUMCVSS out of 10
What this means
Review the available evidence
CVE-2026-56409 and is rated Medium severity with a CVSS score of 6.5. 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: Oct 22, 2026
CBL-Mariner Releases
Vendor-listed releases
2.8.2-1
CISA KEVNot listedBased on the latest collected catalog
EPSS0.1%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2026-56409?
xmlwf in libexpat before 2.8.2 has an integer overflow for the output filename when -d outputDir is used.