Actively exploited in the wild
Linux Kernel Time-of-Check Time-of-Use (TOCTOU) Race Condition Vulnerability
Linux - Kernel · Listed in the CISA KEV since 2025-09-04. This indicates confirmed attacks in production environments.
Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CVE-2025-38352
HighCVSS 7.8KEVExploitation Probability (EPSS)
Elevated risk66th percentile - higher than 66% of all known CVEs
Summary
A race condition was found in the Linux kernel between handle_posix_cpu_timers() and posix_cpu_timer_del(). An exiting non-autoreaping task can be reaped by its parent after unlock_task_sighand(), causing synchronization issues.
Risk Assessment
The organization faces potential system instability, leading to unpredictable process behavior and possible crashes.
Recommendation
Immediately update the Linux kernel to a version containing the fix that adds a tsk->exit_state check in run_posix_cpu_timers().
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: posix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del() If an exiting non-autoreaping task has already passed exit_notify() and calls handle_posix_cpu_timers() from IRQ, it can be reaped by its parent or debugger right after unlock_task_sighand(). If a concurrent posix_cpu_timer_del() runs at that moment, it won't be able to detect timer->it.cpu.firing != 0: cpu_timer_task_rcu() and/or lock_task_sighand() will fail. Add the tsk->exit_state check into run_posix_cpu_timers() to fix this. This fix is not needed if CONFIG_POSIX_CPU_TIMERS_TASK_WORK=y, because exit_task_work() is called before exit_notify(). But the check still makes sense, task_work_add(&tsk->posix_cputimers_work.work) will fail anyway in this case.