# CVE-2025-39771: regulator: pca9450: Use devm_register_sys_off_handler

> A kernel warning and potential crash occur in the PCA9450 regulator driver due to duplicate notifier registration, requiring a patch to use managed resource handling.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Sep 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-39771, DEBIAN-CVE-2025-39771, GHSA-fwgp-x7rw-mmhf, ROOT-OS-UBUNTU-2204-CVE-2025-39771, ROOT-OS-UBUNTU-2404-CVE-2025-39771, UBUNTU-CVE-2025-39771

## What is CVE-2025-39771?

CVE-2025-39771 is a medium-severity denial of service vulnerability in Linux kernel, published on 11 Sep 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:

regulator: pca9450: Use devm_register_sys_off_handler

With module test, there is error dump:
------------[ cut here ]------------
  notifier callback pca9450_i2c_restart_handler already registered
  WARNING: kernel/notifier.c:23 at notifier_chain_register+0x5c/0x88,
  CPU#0: kworker/u16:3/50
  Call trace:
  notifier_chain_register+0x5c/0x88 (P)
  atomic_notifier_chain_register+0x30/0x58
  register_restart_handler+0x1c/0x28
  pca9450_i2c_probe+0x418/0x538
  i2c_device_probe+0x220/0x3d0
  really_probe+0x114/0x410
  __driver_probe_device+0xa0/0x150
  driver_probe_device+0x40/0x114
  __device_attach_driver+0xd4/0x12c

So use devm_register_sys_off_handler to let kernel handle the resource
free to avoid kernel dump.

## Which versions are affected by CVE-2025-39771?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-39771?

Apply the vendor's patch.

## Is CVE-2025-39771 being exploited?

There is no known exploitation of CVE-2025-39771 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-39771 and fix it if it is affected.

What it is: CVE-2025-39771 is a medium-severity denial of service vulnerability in Linux kernel, published on 11 Sep 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-39771 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2025-39771/ (Markdown: https://insights.sbomify.com/CVE-2025-39771/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39771
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39771
- OSV: https://osv.dev/vulnerability/CVE-2025-39771

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-39771/
Summaries are generated and may contain mistakes; the official description above is the record.