KVM: SEV: Check PSC request indices against the actual size of the buffer

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-63938
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: Check PSC request indices against the actual size of the buffer When processing Page State Change (PSC) requests, validate the PSC buffer against the effective size of the scratch area, which could be less than the maximum size if the guest provided a pointer that isn't exactly at the start of the GHCB shared buffer.

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 0.100180000 (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 9b54e248d2644be71cb394eb85f31ad99e023a05 5198f70c09a5f6e9e5f5a0a2c6b388f24294b176 git Not specified
CNA Linux Linux affected 9b54e248d2644be71cb394eb85f31ad99e023a05 75c8d1d7291268b479794fba5808971dc2f5eaf3 git Not specified
CNA Linux Linux affected 9b54e248d2644be71cb394eb85f31ad99e023a05 505a3b94535583e4265360e2621734e355ef263d git Not specified
CNA Linux Linux affected 9b54e248d2644be71cb394eb85f31ad99e023a05 121d88de56bc5c0ba0ce2f6381af67f948a7e7c1 git Not specified
CNA Linux Linux affected 6.11 Not specified
CNA Linux Linux unaffected 6.11 semver Not specified
CNA Linux Linux unaffected 6.12.93 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/5198f70c09a5f6e9e5f5a0a2c6b388f24294b176 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/505a3b94535583e4265360e2621734e355ef263d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/75c8d1d7291268b479794fba5808971dc2f5eaf3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/121d88de56bc5c0ba0ce2f6381af67f948a7e7c1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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