CVE-2026-63937

A flaw was found in the Linux kernel's Kernel-based Virtual Machine KVM with Secure Encrypted Virtualization SEV. This time-of-check to time-of-use TOCTOU vulnerability exists when KVM processes the guest-accessible Page State Change PSC buffer. A misbehaving guest could exploit this timing issue...

CVE-2026-63937 KVM: SEV: Use READ_ONCE() when reading entries/indices from PSC buffer

In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Use READONCE when reading entries/indices from PSC buffer Use READONCE when reading entries/indices from the guest-accessible Page State Change buffer to defend against TOCTOU bugs. Don't bother with READONCE/WRITEONCE...