CVE-2026-98878

irqchip/gic-v5: Immediately exec priority drop following activate

Published Oct 23, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-9019-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9020-1 Linux kernel vulnerabilities
History
Type Values Removed Values Added
Weaknesses CWE-772
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
First Time appeared Linux linux
Weaknesses CWE-760
Vendors & Products Linux linux
Type Values Removed Values Added
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.
Title irqchip/gic-v5: Immediately exec priority drop following activate
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 26, 2026, 6:56 AM
Reserved
Sep 25, 2026, 10:25 AM
Status
Received
Published
Oct 23, 2026, 12:18 PM
Modified
Oct 26, 2026, 7:17 AM
Severity
Moderate
Public date
Oct 23, 2026, 12:00 AM