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CVE-2025-38352

High 7.8 Exploited in the wild (KEV)

Confirmed active exploitation — CISA KEV catalog

Name
Linux Kernel Time-of-Check Time-of-Use (TOCTOU) Race Condition Vulnerability
Added to catalog
Remediation due date (US federal)
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.

Description

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.

Metrics

CVSS 3.1
7.8 (HIGH) Score source: CNA CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS — exploit probability
1% (percentile: 72) as of 1 November 2026
CWE
CWE-367

Affected products

linux: linux kernel; debian: debian linux

References