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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-63940
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-19 16:17:12 UTC
Updated2026-07-20 15:16:57 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 9.3 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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

EPSS: 0.002000000 probability, percentile 0.100220000 (date 2026-07-20)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.3CRITICALCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
3.1CNADECLARED9.3CRITICALCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 291bd20d5d88814a73d43b55b9428feab2f28094 3b6035bc6bff20e89752ce4358bc4c9a9d5883f2 git Not specified
CNA Linux Linux affected 291bd20d5d88814a73d43b55b9428feab2f28094 2254972d4d69e279ba4e87bf0968eb08ad0d3c92 git Not specified
CNA Linux Linux affected 291bd20d5d88814a73d43b55b9428feab2f28094 c30cde934c7813b4e3069765dac64ce3d31e34f2 git Not specified
CNA Linux Linux affected 291bd20d5d88814a73d43b55b9428feab2f28094 3988bd2723de407ae90fa7a6f6029b4e60238c58 git Not specified
CNA Linux Linux affected 5.11 Not specified
CNA Linux Linux unaffected 5.11 semver Not specified
CNA Linux Linux unaffected 6.12.95 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.35 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.12 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/3b6035bc6bff20e89752ce4358bc4c9a9d5883f2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/3988bd2723de407ae90fa7a6f6029b4e60238c58 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2254972d4d69e279ba4e87bf0968eb08ad0d3c92 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c30cde934c7813b4e3069765dac64ce3d31e34f2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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