by Kastro
Paper/Archive/CVE-2026-63938

CVE-2026-63938

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

EPSS 0.2%CVSS 9.3
critical.is priorityof 100
30
CVSS 9.3 (CNA)9.3 / 10 × 3027.9Not in CISA KEV+300.0EPSS percentile 9.3.093 × 201.9No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
Linux9b54e248d2644be71cb394eb85f31ad99e023a05 – < 5198f70c09a5f6e9e5f5a0a2c6b388f24294b1765198f70c09a5f6e9e5f5a0a2c6b388f24294b176CNA
Linux9b54e248d2644be71cb394eb85f31ad99e023a05 – < 75c8d1d7291268b479794fba5808971dc2f5eaf375c8d1d7291268b479794fba5808971dc2f5eaf3CNA
Linux9b54e248d2644be71cb394eb85f31ad99e023a05 – < 505a3b94535583e4265360e2621734e355ef263d505a3b94535583e4265360e2621734e355ef263dCNA
Linux9b54e248d2644be71cb394eb85f31ad99e023a05 – < 121d88de56bc5c0ba0ce2f6381af67f948a7e7c1121d88de56bc5c0ba0ce2f6381af67f948a7e7c1CNA
Linux6.116.12.93CNA

Scores by source

Linux (CNA)9.3CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: total

References

refgit.kernel.org/stable/c/5198f70c09a5f6e9e5f5a0a2c6b388f24294b176refgit.kernel.org/stable/c/75c8d1d7291268b479794fba5808971dc2f5eaf3refgit.kernel.org/stable/c/505a3b94535583e4265360e2621734e355ef263drefgit.kernel.org/stable/c/121d88de56bc5c0ba0ce2f6381af67f948a7e7c1