CVE-2026-98472

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

KVM: SEV: Free have_run_cpus during VM destruction even if VM is no longer SEV

Unconditionally free SEV's "have run CPUs" cpumask in the VM destroy path,

i.e. even for what appear to be non-SEV VMs, as an SEV VM becomes a non-SEV

VM if its state is intra-host migrated. Alternatively, the mask could be

freed in sev_migrate_from() when "converting" the source VM, but that gets

annoying because ideally KVM would nullify the mask to guard against UAF,

and nullifying the mask would need be conditioned on CPUMASK_OFFSTACK=y.

Freeing the mask during sev_migrate_from() is also not robust against other

KVM bugs, though that's kind of a moot point since any such bugs would show

up even if sev->active is never set. I.e. KVM must get that side of things

correct. But, that's not a great reason to add more code just to make

things marginally less robust.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References