Vulnerability in Linux

CVE-2026-63937

In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Use READ_ONCE() when reading entries/indices from PSC buffer Use READ_ONCE() when reading entries/indices from the guest-accessible Page State Change buffer to defend against TOCTOU bugs. Don't bother with READ_ONCE()/WRITE_ONCE() for cases where KVM is writing (and not consuming the result!), as the guest isn't supposed to touch the buffer while it's being processed. I.e. using READ_ONCE() is all about protecting against misbehaving guests.

EPSS: 0.002 (6.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

Affected products

  • Linux — versions 9b54e248d2644be71cb394eb85f31ad99e023a05, 6.11, 0

References

Frequently asked questions

What is CVE-2026-63937?
CVE-2026-63937 is a high-severity vulnerability in Linux. CVSS score: 8.8/10. Published 2026-07-19.
How severe is CVE-2026-63937?
High severity. CVSS v3 base score is 8.8 out of 10.