CVE-2025-38352: Linux Kernel High-Severity Vulnerability

What is CVE-2025-38352?

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.

Technical Analysis

Weakness Classification

This vulnerability is classified as CWE-367.

Attack Vector Breakdown

• Attack Vector: Local
• Attack Complexity: High
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality: High
• Integrity: High
• Availability: High

Impact Analysis

Exploitation requires local access to the target system, such as a local user session or a malicious file opened by a user. Successful exploitation can result in full confidentiality breach (complete data disclosure), complete integrity compromise (data modification or code execution), total availability loss (denial of service).

Exploitation Probability (EPSS): 0.14% chance of exploitation in the next 30 days (33th percentile). While the base probability may appear low, inclusion in CISA KEV confirms real-world exploitation is already occurring.

Exploit Availability

Public exploit code or proof-of-concept is available for CVE-2025-38352. This significantly increases the risk of exploitation, as attackers can use or adapt existing exploit code rather than developing their own. A public exploit reference has been identified. Organizations should treat this as an urgent patching priority.

Is CVE-2025-38352 being exploited?

Yes. CVE-2025-38352 is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, restricted to CVEs with confirmed active exploitation in the wild. CISA added this vulnerability on 2025-09-04. Inclusion in KEV triggers the patching mandate under BOD 22-01 for U.S. federal civilian agencies, with a remediation deadline of 2025-09-25. Additionally, public exploit code is available, which lowers the barrier for attackers.

How to fix CVE-2025-38352

Update the Linux kernel to the patched version via your distribution's package manager (apt, yum, dnf). A reboot is typically required after kernel updates. For environments where rebooting is not immediately possible, check if a livepatch/kpatch is available from your distribution vendor. Check the Linux Kernel CVEs page for the specific patch or update. CISA's Known Exploited Vulnerabilities catalog requires U.S. federal agencies to remediate this vulnerability by the due date shown below under Binding Operational Directive 22-01. Private organizations should treat KEV entries as priority-one patches because active exploitation has been confirmed in the wild.

Related Vulnerabilities

Other actively exploited vulnerabilities affecting Kernel or sharing the same weakness (CWE-367):

• CVE-2022-0492 (High 7.8) [same product] — A vulnerability was found in the Linux kernel’s cgroup_release_agent_write in…
• CVE-2026-31431 (High 7.8) [same product] — In the Linux kernel, the following vulnerability has been resolved: crypto…
• CVE-2018-14634 (High 7.8) [same product] — An integer overflow flaw was found in the Linux kernel's create_elf_tables()…
• CVE-2021-22555 (Unknown N/A) [same product] — Linux Kernel contains a heap out-of-bounds write vulnerability that could…
• CVE-2023-0386 (Unknown N/A) [same product] — Linux Kernel contains an improper ownership management vulnerability, where…

Frequently asked questions

Is CVE-2025-38352 critical?

CVE-2025-38352 has a CVSS 3.1 base score of 7.4 — High severity. It should be treated as a priority patch, especially given the active exploitation confirmed by CISA. The availability of public exploit code further increases the urgency.

Is CVE-2025-38352 being actively exploited?

Yes — CISA added CVE-2025-38352 to the Known Exploited Vulnerabilities catalog on 2025-09-04. Inclusion in KEV means CISA has confirmed in-the-wild exploitation. Public exploit code has also been identified, making exploitation accessible to a broader range of threat actors.

How do I patch CVE-2025-38352?

Apply the security update from Linux for Kernel. Federal agencies must remediate by 2025-09-25 under BOD 22-01. Refer to the Linux Kernel CVEs for the official patch.

What type of vulnerability is CVE-2025-38352?

CVE-2025-38352 is classified under CWE-367.

What is the CVSS score for CVE-2025-38352?

CVE-2025-38352 has a CVSS 3.1 base score of 7.4, classifying it as High severity. The attack vector is Local, attack complexity is High, and no privileges are required.