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.
CSIRTS triage
- What
- Multiple kernel vulnerabilities across architectures and driver subsystems including AMD processor microarchitectural flaws and cache isolation issues.
- Who is affected
- NVIDIA BaseOS systems running affected Linux kernel versions.
- Urgency
- Moderate; privilege escalation and DoS vectors present, primarily requiring local access.
- Action
- Apply USN-8664-1 kernel security update for NVIDIA BaseOS.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.13% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 3% of all EPSS-scored CVEs.
Advisory coverage (8)
- unknownUSN-8729-1: Linux kernel vulnerabilitiesubuntu · 2026-09-07
- unknownexploitedUSN-8728-1: Linux kernel (GCP) vulnerabilitiesubuntu · 2026-09-07
- unknownUSN-8664-1: Linux kernel (NVIDIA BaseOS) vulnerabilitiesubuntu · 2026-08-20
- unknownUSN-8663-1: Linux kernel (NVIDIA) vulnerabilitiesubuntu · 2026-08-20
- highUSN-8618-1: Linux kernel vulnerabilitiesubuntu · 2026-07-28
- highUSN-8603-1: Linux kernel (Azure) vulnerabilitiesubuntu · 2026-07-24
- highUSN-8593-1: Linux kernel vulnerabilitiesubuntu · 2026-07-23
- highCVE-2026-64073: In the Linux kernel, the following vulnerability has been resolved: irq_work: Fix use-after-fr…nvd · 2026-07-19
External references
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