Published Aug 10, 2026Sources checked Oct 28, 2026
5.5MEDIUMCVSS out of 10
What this means
Review the available evidence
CVE-2026-63623 and is rated Medium severity with a CVSS score of 5.5. 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 23, 2026
CBL-Mariner Releases
Vendor-listed releases
10.10.0-3
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-2026-63623?
A flaw was found in libvirt. During storage volume clone or convert operations, newly created volume images were temporarily world-readable.
This was caused by the `qemu-img` utility running with overly permissive file creation settings, allowing any local user to read the full guest disk contents. This vulnerability could lead to sensitive information disclosure from guest virtual machines.