CVE-2026-89727 KVM: arm64: GICv2: Don't WARN on out-of-range GICV_DIR INTID
A malicious guest can trigger a kernel panic on the host by writing an invalid interrupt ID, causing denial of service if panic_on_warn is enabled.
- 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-2026-89727?
CVE-2026-89727 is a denial of service vulnerability in Linux, published on 11 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: GICv2: Don't WARN on out-of-range GICV_DIR INTID
vgic_v2_deactivate() passes the INTID a guest wrote to GICV_DIR straight to vgic_get_vcpu_irq(), and treats a failed lookup as a "can't happen" condition with WARN_ON_ONCE().
The guest can make it happen at will, though: for any INTID outside of the implemented SGI, PPI and SPI ranges the lookup returns NULL, since GICv2 has no LPIs. A guest running with EOImode==1 writing such an INTID to GICV_DIR triggers the WARN, and panics hosts running with panic_on_warn.
Drop the WARN and ignore failed lookups.
Which versions are affected by CVE-2026-89727?
How do I fix CVE-2026-89727?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-89727 being exploited?
There is no known exploitation of CVE-2026-89727 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-89727, GHSA-v32g-7j7h-69wx, UBUNTU-CVE-2026-89727.