CVE intelligence

CVE-2026-31591

Vulnerability intelligence

Published Apr 24, 2026Sources checked Nov 12, 2026

5.5MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2026-31591 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: Apr 29, 2026

CBL-Mariner Releases

Vendor-listed releases

6.6.134.1-2

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-2026-31591?

In the Linux kernel, the following vulnerability has been resolved:

KVM: SEV: Lock all vCPUs when synchronzing VMSAs for SNP launch finish

Lock all vCPUs when synchronizing and encrypting VMSAs for SNP guests, as allowing userspace to manipulate and/or run a vCPU while its state is being synchronized would at best corrupt vCPU state, and at worst crash the host kernel.

Opportunistically assert that vcpu->mutex is held when synchronizing its VMSA (the SEV-ES path already locks vCPUs).

Source: NVD