CVE-2026-63937

Updated on 19 Jul 2026

Severity

Awaiting Analysis

Details

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

Overview

About vulnerability

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.

Details

Affected product:
AlmaLinux 9.2 ESU , TuxCare 9.6 ESU
Affected packages:
kernel @ 5.14.0 (+1 more)

Fixes