# CVE-2025-38352: Linux Kernel Time-of-Check Time-of-Use (TOCTOU) Race Condition

> A race condition in Linux kernel posix-cpu-timers allows a local attacker to cause a denial of service by triggering a use-after-free scenario during task exit.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 4 Sep 2025 (CISA KEV)
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Jul 2025
- **Updated:** 8 Sep 2026
- **Also known as:** A-425282960, ALSA-2025:15662, ASB-A-425282960, BELL-CVE-2025-38352, DEBIAN-CVE-2025-38352, GHSA-mr4j-mh66-4679, RHSA-2025:15662, RLSA-2025:15662, ROOT-OS-DEBIAN-11-CVE-2025-38352, ROOT-OS-DEBIAN-12-CVE-2025-38352, ROOT-OS-UBUNTU-2204-CVE-2025-38352, ROOT-OS-UBUNTU-2404-CVE-2025-38352, UBUNTU-CVE-2025-38352

## What is CVE-2025-38352?

CVE-2025-38352 is a high-severity vulnerability in Debian Debian Linux, published on 22 Jul 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition)

## Which versions are affected by CVE-2025-38352?

It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `kernel-abi-stablelists` | AlmaLinux:10 | All versions | 6.12.0-55.32.1.el10_0 |
| `kernel-doc` | AlmaLinux:10 | All versions | 6.12.0-55.32.1.el10_0 |
| `kernel` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k-core` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k-debug` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k-debug-core` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k-debug-debuginfo` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k-debug-devel` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k-debug-devel-matched` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k-debug-modules` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k-debug-modules-core` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k-debug-modules-extra` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k-debuginfo` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k-devel` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k-devel-matched` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k-modules` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k-modules-core` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-64k-modules-extra` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-abi-stablelists` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-core` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-debug` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-debug-core` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-debug-debuginfo` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-debug-devel` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-debug-devel-matched` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-debug-modules` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-debug-modules-core` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-debug-modules-extra` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-debug-uki-virt` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-debuginfo` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-debuginfo-common-aarch64` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-debuginfo-common-ppc64le` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-debuginfo-common-s390x` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-debuginfo-common-x86_64` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-devel` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-devel-matched` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-modules` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-modules-core` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |
| `kernel-modules-extra` | Red Hat:enterprise_linux:10.0 | All versions | 0:6.12.0-55.32.1.el10_0 |

Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-38352?

Apply the vendor's patch. US federal agencies must fix it by 25 Sep 2025.

## Is CVE-2025-38352 being exploited?

Yes. Attackers have exploited CVE-2025-38352 in the wild since at least 4 Sep 2025.

Public exploit code:

- Android kernel exploit for CVE-2025-38352, previously exploited in-the-wild. Targets vulnerable x86_64 Linux kernels v5.10.x. (github_poc): https://github.com/farazsth98/chronomaly
- This is a proof of concept for CVE-2025-38352, a vulnerability in the Linux kernel's POSIX CPU timers implementation. The September 2025 Android Bulletin mentions that this vulnerability has been used in limited, targeted exploitation in the wild. (github_poc): https://github.com/farazsth98/poc-CVE-2025-38352
- CVE-2025-38352 kernel exploit for LG webOS Smart TVs (ARM64). Achieves persistent root on real consumer hardware with novel exploitation techniques. Responsibly disclosed to LG. (github_poc): https://github.com/AnalyticETH/chronomaly-webos
- The official Sentinel Edition v7.11 - Hypervisor Detection & Kernel Memory Audit Suite for Honor Magic V2. Investigating CVE-2025-38352 and EL2 RKP defenses. (github_poc): https://github.com/jordelmir/Elysium-Vanguard-Sentinel-Audit
- https://github.com/Crime2/poc-CVE-2025-38352 (github_poc): https://github.com/Crime2/poc-CVE-2025-38352
- PoC and GDB script assists in triggering CVE-2025-38352 (github_poc): https://github.com/longwasu/CVE-2025-38352-PoC

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-38352 and fix it if it is affected.

What it is: CVE-2025-38352 is a high-severity vulnerability in Debian Debian Linux, published on 22 Jul 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2025-38352 in the wild since at least 4 Sep 2025.

Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-38352/ (Markdown: https://insights.sbomify.com/CVE-2025-38352/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38352
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38352
- OSV: https://osv.dev/vulnerability/CVE-2025-38352

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38352/
Summaries are generated and may contain mistakes; the official description above is the record.