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CVE-2026-63938

CRITICALCVSS 9.3/10EPSS 0.18%

Last modified

CVE-2026-63938 is a critical-severity vulnerability rated 9.3/10 on the CVSS scale. 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.. EPSS estimates a 0.18% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
9.3/10

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

EPSS Probability
0.18%

7.8th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 9b54e248d2644be71cb394eb85f31ad99e023a05, < 5198f70c09a5f6e9e5f5a0a2c6b388f24294b176; >= 9b54e248d2644be71cb394eb85f31ad99e023a05, < 75c8d1d7291268b479794fba5808971dc2f5eaf3; >= 9b54e248d2644be71cb394eb85f31ad99e023a05, < 505a3b94535583e4265360e2621734e355ef263d; >= 9b54e248d2644be71cb394eb85f31ad99e023a05, < 121d88de56bc5c0ba0ce2f6381af67f948a7e7c1
LinuxLinux6.11

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-63938?
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.
How severe is CVE-2026-63938?
CVE-2026-63938 has a CVSS score of 9.3/10 (CRITICAL severity). The EPSS model estimates a 0.18% probability of exploitation in the next 30 days.
How do I fix CVE-2026-63938?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST