CVE-2026-89922 KVM: s390: Take srcu when importing watchpoint data
A race condition in Linux KVM s390 watchpoint handling can lead to a use-after-free, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-89922?
CVE-2026-89922 is a high-severity vulnerability in Linux, published on 16 Sep 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: s390: Take srcu when importing watchpoint data
__import_wp_info() backs up the original guest memory contents of a watchpoint with read_guest_abs(), which is kvm_read_guest() and therefore resolves the memslot via __kvm_memslots(). That requires kvm->srcu (or kvm->slots_lock) to be held, otherwise a concurrent memslot update can free the memslots array under us once its SRCU grace period has elapsed.
As this is not fast path, following lock ordering (mutex first, then srcu) take the big hammer and hold the srcu for the full import.
Which versions are affected by CVE-2026-89922?
How do I fix CVE-2026-89922?
Apply the vendor's patch.
Is CVE-2026-89922 being exploited?
There is no known exploitation of CVE-2026-89922 in the wild and no public exploit code.
Sources
Also known as AZL-101468, BELL-CVE-2026-89922, DEBIAN-CVE-2026-89922, GHSA-x4qh-jwqp-j7jf, UBUNTU-CVE-2026-89922.