CVE-2026-63940 | In the Linux kernel, the following vulnerability has been re… | CVSS 9.3 CRITICAL

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.

Metadata

CVE ID: CVE-2026-63940
State: PUBLISHED
Assigner: Linux
Reserved: 2026-07-19 07:54 UTC
Published: 2026-07-19 14:55 UTC
Last updated: 2026-07-20 13:41 UTC
Vendor / Product: Linux / Linux
Sources: cve.org · NVD

Severity & Metrics

9.3 CRITICAL CVSS 3.1

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

Affected products (2)

Vendor	Product	Platform	Versions
Linux	Linux	—	291bd20d5d88814a73d43b55b9428feab2f28094 < 3b6035bc6bff20e89752ce4358bc4c9a9d5883f2, 291bd20d5d88814a73d43b55b9428feab2f28094 < 2254972d4d69e279ba4e87bf0968eb08ad0d3c92, 291bd20d5d88814a73d43b55b9428feab2f28094 < c30cde934c7813b4e3069765dac64ce3d31e34f2, 291bd20d5d88814a73d43b55b9428feab2f28094 < 3988bd2723de407ae90fa7a6f6029b4e60238c58
Linux	Linux	—	5.11, 0 < 5.11, 6.12.95 ≤ 6.12., 6.18.35 ≤ 6.18. …

CVSS scores (1)

Score	Severity	Version	Source	Vector
9.3	CRITICAL	3.1	cna	CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

References (4)