# CVE-2025-39954: clk: sunxi-ng: mp: Fix dual-divider clock rate readback

> A missing divider offset in the Linux kernel clock driver causes divide-by-zero errors, potentially leading to system crashes or denial of service.

- **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:** 9 Oct 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-39954, DEBIAN-CVE-2025-39954, GHSA-g295-3qg8-vf4w, UBUNTU-CVE-2025-39954

## What is CVE-2025-39954?

CVE-2025-39954 is a medium-severity denial of service vulnerability in Linux kernel, published on 9 Oct 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:

clk: sunxi-ng: mp: Fix dual-divider clock rate readback

When dual-divider clock support was introduced, the P divider offset was
left out of the .recalc_rate readback function. This causes the clock
rate to become bogus or even zero (possibly due to the P divider being
1, leading to a divide-by-zero).

Fix this by incorporating the P divider offset into the calculation.

Weakness: CWE-369 (Divide By Zero)

## Which versions are affected by CVE-2025-39954?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-39954?

Apply the vendor's patch.

## Is CVE-2025-39954 being exploited?

There is no known exploitation of CVE-2025-39954 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-2025-39954 and fix it if it is affected.

What it is: CVE-2025-39954 is a medium-severity denial of service vulnerability in Linux kernel, published on 9 Oct 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-2025-39954 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-2025-39954/ (Markdown: https://insights.sbomify.com/CVE-2025-39954/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39954
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39954
- OSV: https://osv.dev/vulnerability/CVE-2025-39954

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-39954/
Summaries are generated and may contain mistakes; the official description above is the record.