CVE-2025-38352

posix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del()

Published Jul 22, 2025 CVSS 3.1 · 7.8 High EPSS 1.4% KEV · Listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4327-1 linux security update
Debian DLA Debian DLA DLA-4328-1 linux-6.1 security update
Debian DSA Debian DSA DSA-5973-1 linux security update
EUVD EUVD EUVD-2025-22297 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.
Ubuntu USN Ubuntu USN USN-7769-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7769-2 Linux kernel (Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-7769-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7770-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-7771-1 Linux kernel (OEM) vulnerabilities
Ubuntu USN Ubuntu USN USN-7774-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7774-2 Linux kernel (FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7774-3 Linux kernel (Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-7775-1 Linux kernel (Azure FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7775-2 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-7776-1 Linux kernel (Oracle) vulnerabilities
Ubuntu USN Ubuntu USN USN-7775-3 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-7774-4 Linux kernel (KVM) vulnerabilities
Ubuntu USN Ubuntu USN USN-7789-1 Linux kernel (Oracle) vulnerabilities
Ubuntu USN Ubuntu USN USN-7774-5 Linux kernel (NVIDIA Tegra IGX) vulnerabilities
Ubuntu USN Ubuntu USN USN-7789-2 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-7853-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7853-2 Linux kernel (FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7854-1 Linux kernel (KVM) vulnerabilities
Ubuntu USN Ubuntu USN USN-7861-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7863-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7861-2 Linux kernel (Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-7864-1 Linux kernel (GCP and GKE) vulnerabilities
Ubuntu USN Ubuntu USN USN-7853-3 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-7865-1 Linux kernel (FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7861-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7874-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7874-2 Linux kernel (FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7861-4 Linux kernel (AWS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7875-1 Linux kernel (Oracle) vulnerabilities
Ubuntu USN Ubuntu USN USN-7861-5 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7874-3 Linux kernel (IoT) vulnerabilities
Ubuntu USN Ubuntu USN USN-7935-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-7937-1 Linux kernel (Azure FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7939-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-7939-2 Linux kernel (Azure FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7940-1 Linux kernel (Azure FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-7940-2 Linux kernel (Azure, N-Series) vulnerabilities
Ubuntu USN Ubuntu USN USN-7986-1 Linux kernel vulnerabilities
History
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
First Time appeared Debian
Debian debian Linux
CPEs cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
Vendors & Products Debian
Debian debian Linux
Type Values Removed Values Added
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.16:rc1:*:*:*:*:*:*
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'active', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Metrics kev

{'dateAdded': '2025-09-04T00:00:00+00:00', 'dueDate': '2025-09-25T00:00:00+00:00'}

Type Values Removed Values Added
Weaknesses CWE-362
Type Values Removed Values Added
Weaknesses CWE-367
Type Values Removed Values Added
Weaknesses CWE-362
Metrics cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Vendors & Products Linux
Linux linux Kernel
Type Values Removed Values Added
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.
Title posix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del()
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Sep 8, 2026, 3:32 PM
Reserved
Apr 16, 2025, 4:51 AM
Status
Analyzed
Published
Jul 22, 2025, 8:15 AM
Modified
Sep 8, 2026, 6:17 PM
Severity
Moderate
Public date
Jul 22, 2025, 12:00 AM