CVE-2026-64073

In the Linux kernel, the following vulnerability has been resolved: irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT On PREEMPT_RT, non-HARD irq_work runs in per-CPU kthreads via run_irq_workd(), so irq_work_sync() uses rcuwait() to wait for BUSY==0. After irq_work_single() clears BUSY via atomic_cmpxchg(), it still dereferences @work for irq_work_is_hard() and rcuwait_wake_up(). An irq_work_sync() caller on another CPU that enters after BUSY is cleared can observe BUSY==0 immediately, return, and free the work before those accesses complete — causing a use-after-free. Fix this by wrapping run_irq_workd() in guard(rcu)() so that the entire irq_work_single() execution is within an RCU read-side critical section. Then add synchronize_rcu() in irq_work_sync() after rcuwait_wait_event() to ensure the caller waits for the RCU grace period before returning, preventing premature frees.

What this means for your business

It affects Linux Kernel. It matters if your company, or a supplier that handles your data, runs it.
An attacker can use it only with access to the machine itself, with an ordinary user login, and without anyone at your company clicking anything.
FIRST's prediction model gives it a 0.1% chance of attack attempts being seen in the next 30 days, ranking above 2% of all known flaws.

What to do

1Check whether your company or your suppliers run Linux Kernel, and which version. The affected versions are listed further down this page.
2If you do, apply the vendor's fix. A patch or vendor advisory has been published.

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Scoring

CVSS: 7.8 (v3.1)
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-416
Assigned by: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Dates

Published: 2026-07-19
Last modified: 2026-09-03
Sources: NVD

Affected products

Linux Linux Kernel5.16 - 6.1.175, 6.2 - 6.6.142, 6.7 - 6.12.92, 6.13 - 6.18.34, 6.19 - 7.0.11, 7.1

As listed in the NVD configuration data. Not a statement about your estate.