---
title: "CVE-2025-38352: Linux Kernel Time-of-Check Time-of-Use (TOCTOU) Race Condition Vulnerability"
url: https://erroneo.us/security/cve/CVE-2025-38352/
description: "CVE-2025-38352 (Linux Kernel): Exploited in the wild (CISA KEV). In the Linux kernel, the following vulnerability has been resolved: posix-cpu-timers: fix…"
type: vulnerability-record
section: "Security Digest"
date_published: 2025-07-22
date_modified: 2026-09-08
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2025-38352"
kev: true
cvss: 7.8
epss: 0.01341
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Linux Kernel. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2025-09-04, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2025-09-25 ; treat that as the outer limit, not the target.
- EPSS 1.3% , percentile 71: FIRST’s model estimates a 1.3% chance of exploitation activity in the next 30 days, higher than 71% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Needs local access needed. Lower urgency for most teams unless an attacker could already run code on the machine.

## What it is

In the Linux kernel, the following vulnerability has been resolved: posix-cpu-timers: fix race between handleposixcputimers() and posixcputimerdel() If an exiting non-autoreaping task has already passed exitnotify() and calls handleposixcputimers() from IRQ, it can be reaped by its parent or debugger right after unlocktasksighand(). If a concurrent posixcputimerdel() runs at that moment, it won't be able to detect timer->it.cpu.firing != 0: cputimertaskrcu() and/or locktasksighand() will fail. Add the tsk->exitstate check into runposixcputimers() to fix this. This fix is not needed if CONFIGPOSIXCPUTIMERSTASKWORK=y, because exittaskwork() is called before exitnotify(). But the check still makes sense, taskworkadd(&tsk->posixcputimerswork.work) will fail anyway in this case.

## Affected products (CVE record)

- Linux Linux: 0bdd2ed4138ec04e09b4f8165981efc99e439f55 < 78a4b8e3795b31dae58762bc091bb0f4f74a2200, 0bdd2ed4138ec04e09b4f8165981efc99e439f55 < c076635b3a42771ace7d276de8dc3bc76ee2ba1b, 0bdd2ed4138ec04e09b4f8165981efc99e439f55 < 2f3daa04a9328220de46f0d5c919a6c0073a9f0b, 0bdd2ed4138ec04e09b4f8165981efc99e439f55 < 764a7a5dfda23f69919441f2eac2a83e7db6e5bb, 0bdd2ed4138ec04e09b4f8165981efc99e439f55 < 2c72fe18cc5f9f1750f5bc148cf1c94c29e106ff, 0bdd2ed4138ec04e09b4f8165981efc99e439f55 < c29d5318708e67ac13c1b6fc1007d179fb65b4d7, 0bdd2ed4138ec04e09b4f8165981efc99e439f55 < 460188bc042a3f40f72d34b9f7fc6ee66b0b757b, 0bdd2ed4138ec04e09b4f8165981efc99e439f55 < f90fff1e152dedf52b932240ebbd670d83330eca
- Linux Linux: 2.6.36

## Severity

- Linux CVSS 3.1: 7.8 `CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: added 2025-09-04; federal due date 2025-09-25. Known ransomware use: Unknown.
- CISA 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.
- CISA SSVC assessment: exploitation active , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 1.34% probability of exploitation activity in the next 30 days; percentile 71.

## Sources

- [Listed in CISA KEV notes (git.kernel.org)](https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2c72fe18cc5f9f1750f5bc148cf1c94c29e106ff)
- [Listed in CISA KEV notes (source.android.com)](https://source.android.com/docs/security/bulletin/2025-09-01)
- [CVE.org record CVE-2025-38352](https://www.cve.org/CVERecord?id=CVE-2025-38352)
- [NVD entry CVE-2025-38352](https://nvd.nist.gov/vuln/detail/CVE-2025-38352)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-38352)
- [git.kernel.org](https://git.kernel.org/stable/c/78a4b8e3795b31dae58762bc091bb0f4f74a2200)
- [git.kernel.org](https://git.kernel.org/stable/c/c076635b3a42771ace7d276de8dc3bc76ee2ba1b)
- [git.kernel.org](https://git.kernel.org/stable/c/2f3daa04a9328220de46f0d5c919a6c0073a9f0b)
- [git.kernel.org](https://git.kernel.org/stable/c/764a7a5dfda23f69919441f2eac2a83e7db6e5bb)
- [git.kernel.org](https://git.kernel.org/stable/c/2c72fe18cc5f9f1750f5bc148cf1c94c29e106ff)
- [git.kernel.org](https://git.kernel.org/stable/c/c29d5318708e67ac13c1b6fc1007d179fb65b4d7)
- [git.kernel.org](https://git.kernel.org/stable/c/460188bc042a3f40f72d34b9f7fc6ee66b0b757b)
- [git.kernel.org](https://git.kernel.org/stable/c/f90fff1e152dedf52b932240ebbd670d83330eca)
- [github.com](https://github.com/farazsth98/chronomaly)
- [lists.debian.org](https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html)
- [lists.debian.org](https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html)

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Source page: https://erroneo.us/security/cve/CVE-2025-38352/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt