The vulnerability in the Linux kernel affects irq_work_single() on PREEMPT_RT systems where non-HARD irq_work runs in per-CPU kernel threads. After irq_work_single() clears the BUSY flag using atomic operations, it still dereferences the work structure for further checks. Meanwhile, another CPU may observe BUSY as cleared and free the work structure prematurely, causing a use-after-free condition. The patch wraps run_irq_workd() in an RCU read-side critical section and adds synchronize_rcu() in irq_work_sync() to ensure the caller waits for the RCU grace period before returning, preventing premature freeing and use-after-free.

This vulnerability can lead to use-after-free memory corruption in the Linux kernel on PREEMPT_RT configurations. Such memory corruption could potentially cause system instability, crashes, or escalation of privileges if exploited. However, no known exploits are reported in the wild at this time.

A fix for this vulnerability has been implemented in the Linux kernel by introducing RCU synchronization mechanisms to prevent premature freeing of irq_work structures. Users should apply the official Linux kernel updates that include this fix. Since no vendor advisory or patch links are provided, check the Linux kernel mailing lists or official repositories for the relevant patch and update guidance. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance.