CVE-2026-64073
Description
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.
How to fix
- linux linux_kernel6.1.175, 6.6.142, 6.12.92, 6.18.34, 7.0.11 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linux linux_kernel | 5.16 ≤ v < 6.1.175, 6.2 ≤ v < 6.6.142, 6.7 ≤ v < 6.12.92, 6.13 ≤ v < 6.18.34, 6.19 ≤ v < 7.0.11, 7.1 | 6.1.175, 6.6.142, 6.12.92, 6.18.34, 7.0.11 |
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