CVE-2026-63940

CriticalCVSS 9.3/10Last modified Oct 21, 2026

Description

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

KVM: SEV: Ignore Port I/O requests of length '0'

Explicitly ignore Port I/O requests of length '0' (or count '0'), so that setting up the software scratch area (and other code) doesn't have to worry about underflowing the length, and to allow for WARNing on trying to configure the scratch area with len==0.

Metrics

CVSS 3.1 9.3/10CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Weakness enumeration

CWE-190

Affected software

Source: the vendor's advisory (CNA). NVD analysis pending.

No affected versions have been published.

Timeline

Published
Jul 19, 2026
Last modified
Oct 21, 2026
NVD status
Undergoing Analysis

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CVE-2026-63940: Critical severity, CVSS 9.3 | Vulnix