CVE-2026-90304 ARM: 9484/1: enable interrupts when unhandled user faults are triggered
A local attacker can cause a denial of service in the Linux kernel by triggering unhandled user faults with interrupts disabled under specific PREEMPT_RT configurations.
- 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-2026-90304?
CVE-2026-90304 is a denial of service vulnerability in Linux, published on 17 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:
ARM: 9484/1: enable interrupts when unhandled user faults are triggered
PREEMPT_RT requires interrupts to be enabled when sending signals.
When do_DataAbort()/do_PrefetchAbort() triggers unhandled user faults, that is `inf->fn()` return a non-zero value, and the interrupts are not enabled within the hook function, force_sig_fault() will be called with interrupts disabled.
This can be triggered by user programs executing the bkpt instruction, with kernel config CONFIG_PERF_EVENTS=n.
Enable interrupts in do_DataAbort()/do_PrefetchAbort() when unhandled user faults are triggered to fix the issue.
Which versions are affected by CVE-2026-90304?
How do I fix CVE-2026-90304?
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-2026-90304 being exploited?
There is no known exploitation of CVE-2026-90304 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-90304, GHSA-xgwf-qw68-fxv2, UBUNTU-CVE-2026-90304.