# What is CVE-2025-38352?

> CVE-2025-38352 is a high-severity flaw (CVSS 7.4) in Linux kernel, published on 22 July 2025. It is on the list of flaws known to be exploited, so criminals are already using it. The latest forecast puts its chance of use in the next 30 days at 1.3%. If you run an affected version, patch it first.

Canonical page: https://www.edgeprotect.io/what-is/cve-2025-38352

## At a glance

- **Verdict:** Fix this now. Attackers are using this flaw today. If you run an affected version, it goes to the top of your list.
- **EdgeProtect risk score:** 74 out of 100 (High); action: Emergency patch. Kept up to date as the evidence changes.
- **Severity:** High (CVSS 7.4 out of 10)
- **Known to be exploited:** Yes, it is on the government list of flaws known to be exploited
- **Chance of use in the next 30 days:** 1.3% (latest exploit-likelihood forecast)
- **Published:** 22 July 2025
- **Record last updated:** 5 September 2025
- **Main product:** Linux kernel
- **Affected products:** 1

## What is CVE-2025-38352? In plain terms

An attacker has to be already on the device without logging in, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.

### The 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.

### What kind of flaw is it?

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

### How an attack on it works

- Where an attacker can be: Already on the device
- How hard it is to pull off: Hard: conditions must line up
- Login needed first: No login needed
- Does someone have to click: No, nobody has to do anything
- What an attacker gets: Can read data, change data and take it offline

Severity vector: `CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Is CVE-2025-38352 being exploited? Yes

Attackers are already using it. It is on the government list of flaws known to be exploited, and the latest forecast puts the chance of it being used in the next 30 days at 1.3%.

Exploit likelihood over the last 7 days: 1.3%, 1.3%, 1.3%, 1.3%, 1.3%, 1.3%, 1.3%.

### Timeline

- 22 July 2025: Published
- 5 September 2025: Added to the known-exploited list
- 5 September 2025: Record last updated

### How EdgeProtect ranks it

CVE-2025-38352 scores **74 out of 100 (High)**, with the action "Emergency patch".

Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less:

- Evidence it is being exploited: biggest factor
- How severe it is: strong factor
- How widely exposed it is: key context
- Real threat activity around it: key context

85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it.

## Who is affected by CVE-2025-38352?

The published record lists 1 product. Versions are as published: "2.6.36 to before 5.4.295" means from 2.6.36 up to, but not including, 5.4.295.

- [Linux kernel](https://www.edgeprotect.io/product/linux/linux_kernel) by [Linux](https://www.edgeprotect.io/vendors/linux) (Operating system): 2.6.36 to before 5.4.295, 5.5 to before 5.10.239, 5.11 to before 5.15.186, 5.16 to before 6.1.142, 6.2 to before 6.6.94, 6.7 to before 6.12.34, 6.13 to before 6.15.3, 6.16-rc1

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

1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? EdgeProtect can work it out from your public website, or you can pick it from a list.
2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisories and patch notes first in the list.
3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
4. **Check it wasn’t used before you patched.** Because criminals are already using this flaw, look for signs of a break-in on affected systems using the vendor’s guidance.

### References

- [git.kernel.org](https://git.kernel.org/stable/c/2c72fe18cc5f9f1750f5bc148cf1c94c29e106ff) (Patch)
- [git.kernel.org](https://git.kernel.org/stable/c/2f3daa04a9328220de46f0d5c919a6c0073a9f0b) (Patch)
- [git.kernel.org](https://git.kernel.org/stable/c/460188bc042a3f40f72d34b9f7fc6ee66b0b757b) (Patch)
- [git.kernel.org](https://git.kernel.org/stable/c/764a7a5dfda23f69919441f2eac2a83e7db6e5bb) (Patch)
- [git.kernel.org](https://git.kernel.org/stable/c/78a4b8e3795b31dae58762bc091bb0f4f74a2200) (Patch)
- [git.kernel.org](https://git.kernel.org/stable/c/c076635b3a42771ace7d276de8dc3bc76ee2ba1b) (Patch)
- [git.kernel.org](https://git.kernel.org/stable/c/c29d5318708e67ac13c1b6fc1007d179fb65b4d7) (Patch)
- [git.kernel.org](https://git.kernel.org/stable/c/f90fff1e152dedf52b932240ebbd670d83330eca) (Patch)

## Questions

### What is CVE-2025-38352?

CVE-2025-38352 is a high-severity flaw in Linux kernel, published on 22 July 2025. An attacker has to be already on the device without logging in, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.

### How serious is CVE-2025-38352?

It scores 7.4 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2025-38352 is 74 out of 100, which is High. Its action is "Emergency patch". Attackers are using this flaw today. If you run an affected version, it goes to the top of your list.

### Is CVE-2025-38352 being exploited?

Attackers are already using it. It is on the government list of flaws known to be exploited, and the latest forecast puts the chance of it being used in the next 30 days at 1.3%.

### Which versions does CVE-2025-38352 affect?

For Linux kernel: 2.6.36 to before 5.4.295, 5.5 to before 5.10.239, 5.11 to before 5.15.186, 5.16 to before 6.1.142, 6.2 to before 6.6.94, 6.7 to before 6.12.34 and 2 more.

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

Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet. Because criminals are already using it, also check affected systems for signs of a break-in.

## Does CVE-2025-38352 affect you?

EdgeProtect keeps checking for you:

- **Tell us what you run.** Pick your software from a list, or let us work it out from your website.
- **We match it to every flaw.** Over 400,000 published flaws, checked against your list.
- **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it.
- **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools.

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