CVE-2026-98878 irqchip/gic-v5: Immediately exec priority drop following activate
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-98878?
CVE-2026-98878 is a vulnerability in Linux, published on 23 Oct 2026.
Official description
In the Linux kernel, the following vulnerability has been resolved:
irqchip/gic-v5: Immediately exec priority drop following activate
With GICv5 an interrupt of equal or lower priority cannot be signalled until there has been a priority drop. This is done via the GIC CDEOI system instruction. Once this has been executed, the hardware is able to signal the next interrupt if there is one.
As all interrupts are programmed to have the same priority, no new interrupts can be signalled until the priority drop has happened. This can cause issues when, for example, an interrupt remains active while a long running process takes place, such as when injecting a physical interrupt into a guest VM in software.
The GICv5 driver has so far done the priority drop as part of irq_eoi(), i.e., at the same time as deactivating the interrupt. This means that any long running process (or VM) could block incoming interrupts, effectively causing a denial of service for all other interrupts.
Rather than doing the EOI as part of irq_eoi() (which the name would suggest would be a good place for it), move it to happen immediately after acknowledging an interrupt in the main GICv5 interrupt handler. The deactivation of interrupts (GIC CDDI) remains implemented as part of irq_eoi(), which means that the same interrupt cannot be signalled a second time until deactivated by software.
Which versions are affected by CVE-2026-98878?
How do I fix CVE-2026-98878?
Upgrade to a fixed version.
Is CVE-2026-98878 being exploited?
There is no known exploitation of CVE-2026-98878 in the wild and no public exploit code.
Sources
Also known as AZL-110558, BELL-CVE-2026-98878, DEBIAN-CVE-2026-98878, GHSA-w79p-wpg5-4m55, UBUNTU-CVE-2026-98878.