CVE-2026-98637 KVM: arm64: Do not clear VM-wide SVE feature on vCPU init failure
A null pointer dereference in KVM arm64 allows a local attacker to cause a denial of service by triggering a guest floating-point access after a failed vCPU initialization.
- 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-2026-98637?
CVE-2026-98637 is a 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: arm64: Do not clear VM-wide SVE feature on vCPU init failure
pkvm_vcpu_init_sve() clears KVM_ARM_VCPU_SVE in kvm->arch.vcpu_features when it fails, but vcpu_has_sve() tests KVM_ARCH_FLAG_GUEST_HAS_SVE, which is left set. Later vCPUs on that VM then skip the SVE setup and register with a NULL sve_state, which the guest's first FP access hands to sve_load_state().
Return the error without touching vcpu_features.
Which versions are affected by CVE-2026-98637?
How do I fix CVE-2026-98637?
Apply the vendor's patch.
Is CVE-2026-98637 being exploited?
There is no known exploitation of CVE-2026-98637 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-98637, DEBIAN-CVE-2026-98637, GHSA-j9wj-wgv2-phcm, UBUNTU-CVE-2026-98637.