CVE-2026-63938

Linux kernel vulnerability

9.3 CRITICALEPSS 0.20%

Published19 Jul 2026

Description

In 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.

CVSS 3.1 breakdown

Attack vectorLocal

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeChanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

Frequently asked

Is CVE-2026-63938 being actively exploited?

CVE-2026-63938 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.20%.

How severe is CVE-2026-63938?

CVE-2026-63938 has a CVSS 3.1 base score of 9.3, rated critical. EPSS estimates a 0.20% probability of exploitation.

How do I fix CVE-2026-63938?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-63938 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.