CVE-2026-80873 KVM: arm64: nv: Write ESR_EL2 for injected nested SError exceptions
A guest L2 hypervisor can read stale ESR_EL2 values due to missing syndrome writes for nested SError exceptions in the Linux kernel KVM module.
- 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-2026-80873?
CVE-2026-80873 is a vulnerability in Linux, published on 4 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: arm64: nv: Write ESR_EL2 for injected nested SError exceptions
kvm_inject_el2_exception() writes ESR_EL2 for synchronous exceptions but not for SError. enter_exception64() does not write ESR_ELx for any exception type, so the constructed syndrome is dropped. A guest L2 hypervisor taking a nested SError observes stale ESR_EL2.
This affects both kvm_inject_nested_serror() and the EASE path in kvm_inject_nested_sea().
Write ESR_EL2 for except_type_serror, matching except_type_sync.
Which versions are affected by CVE-2026-80873?
How do I fix CVE-2026-80873?
Apply the vendor's patch.
Is CVE-2026-80873 being exploited?
There is no known exploitation of CVE-2026-80873 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-80873, DEBIAN-CVE-2026-80873, GHSA-hw7g-293v-4f3g, UBUNTU-CVE-2026-80873.