CVE-2026-98471 KVM: SEV: Do cache maintenance on the source VM during intra-host migration
A local attacker with high privileges can read stale data from CPU caches during KVM SEV intra-host migration due to missing cache maintenance on the source VM.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98471?
CVE-2026-98471 is a high-severity vulnerability in Linux, published on 18 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
KVM: SEV: Do cache maintenance on the source VM during intra-host migration
Manually perform cache maintenance on the source VM during intra-host migration to ensure no stale data is left in CPU caches after the VM is destroyed. Because the source VM is "converted" to a non-SEV VM, KVM's memory reclaim flows won't trigger cache maintenance, e.g. when all guest memory is reclaimed in response to detaching from the mmu_notifier.
Note, relying on the destination VM to do cache maintenance isn't an option as KVM doesn't require identical guest memory configurations, i.e. the source VM may have access to memory that the destination VM does not. Enforcing equivalent memory configurations is infeasible, as it would require a *deep* comparison of memslots, e.g. to verify that not only are the memslot identical, but what the memslots point at is also identical.
Which versions are affected by CVE-2026-98471?
How do I fix CVE-2026-98471?
Apply the vendor's patch.
Is CVE-2026-98471 being exploited?
There is no known exploitation of CVE-2026-98471 in the wild and no public exploit code.
Sources
Also known as AZL-108702, BELL-CVE-2026-98471, DEBIAN-CVE-2026-98471, GHSA-hqmw-j6g2-75m9, UBUNTU-CVE-2026-98471.