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CVE-2025-38352

Linux Kernel Time-of-Check Time-of-Use (TOCTOU) Race Condition

7.8 HIGHActively exploited (CISA KEV)Public exploitEPSS 1.29%
  1. Published22 Jul 2025
  2. Added to CISA KEV4 Sept 2025
  3. Remediation due25 Sept 2025
Actively exploited (CISA KEV)

Linux kernel contains a time-of-check time-of-use (TOCTOU) race condition vulnerability that has a high impact on confidentiality, integrity, and availability.

Added to KEV: 4 Sept 2025Federal remediation due: 25 Sept 2025

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.

CVSS 3.1 breakdown

Attack vectorLocal
Attack complexityLow
Privileges requiredLow
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Debian Linux11.0
Linux Kernel≥ 2.6.36 < 5.4.295 · ≥ 5.11 < 5.15.186 · ≥ 5.16 < 6.1.142 · ≥ 5.5 < 5.10.239

Remediation

Fixed in
Linux Kernel≥ 5.4.295

References

and 2 more references

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Frequently asked

Is CVE-2025-38352 being actively exploited?

Yes. CVE-2025-38352 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 4 Sept 2025.

How severe is CVE-2025-38352?

CVE-2025-38352 has a CVSS 3.1 base score of 7.8, rated high. EPSS estimates a 1.29% probability of exploitation.

Which products are affected by CVE-2025-38352?

Affected products include Debian Linux, Linux Kernel.

How do I fix CVE-2025-38352?

Upgrade affected software to a fixed version, for example Linux Kernel 5.4.295 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2025-38352 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.