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.
Affected versions
Linux kernel versions
5.16
and later are affected. Fixed in
6.1.175,
6.6.142,
6.12.92,
6.18.34,
7.0.11,
7.1
and their respective stable series.
References
6 totalFrequently asked questions
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What is CVE-2026-64073?
CVE-2026-64073 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 5.16 onward and has been patched in 6.1.175, 6.6.142, 6.12.92 and others. CVE-2026-64073 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-64073?
Yes — CVE-2026-64073 has been patched. Fixed versions include 6.1.175, 6.6.142, 6.12.92 and others. If you are running Linux kernel 5.16 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-64073 actively exploited?
No — CVE-2026-64073 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.