CVE-2026-64555 KVM: arm64: nv: Fix SPSR_EL2 restore in kvm_hyp_handle_mops()
A missing state translation in KVM arm64 nested virtualization allows guest control over host registers, potentially enabling privilege escalation or code execution.
- 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-2026-64555?
CVE-2026-64555 is a high-severity vulnerability in Linux, published on 27 Jul 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: nv: Fix SPSR_EL2 restore in kvm_hyp_handle_mops()
kvm_hyp_handle_mops() resets the single-step state machine as part of rewinding state for a MOPS exception by modifying vcpu_cpsr() and writing the result directly into hardware.
In the case of nested virtualization, vcpu_cpsr() is a synthetic value such that the rest of KVM can deal with vEL2 cleanly. That means the value requires translation before being written into hardware, which is unfortunately missing from the MOPS handler.
Fix it by directly modifying SPSR_EL2 and avoiding the synthetic state altogether, which will be resynchronized on the next 'full' exit back to KVM.
Which versions are affected by CVE-2026-64555?
How do I fix CVE-2026-64555?
Apply the vendor's patch.
Is CVE-2026-64555 being exploited?
There is no known exploitation of CVE-2026-64555 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-64555, DEBIAN-CVE-2026-64555, GHSA-mh5j-7pgc-m97g, UBUNTU-CVE-2026-64555.