# CVE-2025-38633: clk: spacemit: mark K1 pll1_d8 as critical

> A logic error in the Linux kernel clock driver allows disabling a critical parent clock, causing a system hang and 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:** 22 Aug 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-38633, GHSA-xp55-qmgg-q2rh, UBUNTU-CVE-2025-38633

## What is CVE-2025-38633?

CVE-2025-38633 is a medium-severity denial of service vulnerability in Linux kernel, published on 22 Aug 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: spacemit: mark K1 pll1_d8 as critical

The pll1_d8 clock is enabled by the boot loader, and is ultimately a
parent for numerous clocks, including those used by APB and AXI buses.
Guodong Xu discovered that this clock got disabled while responding to
getting -EPROBE_DEFER when requesting a reset controller.

The needed clock (CLK_DMA, along with its parents) had already been
enabled.  To respond to the probe deferral return, the CLK_DMA clock
was disabled, and this led to parent clocks also reducing their enable
count.  When the enable count for pll1_d8 was decremented it became 0,
which caused it to be disabled.  This led to a system hang.

Marking that clock critical resolves this by preventing it from being
disabled.

Define a new macro CCU_FACTOR_GATE_DEFINE() to allow clock flags to
be supplied for a CCU_FACTOR_GATE clock.

## Which versions are affected by CVE-2025-38633?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-38633?

Apply the vendor's patch.

## Is CVE-2025-38633 being exploited?

There is no known exploitation of CVE-2025-38633 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-2025-38633 and fix it if it is affected.

What it is: CVE-2025-38633 is a medium-severity denial of service vulnerability in Linux kernel, published on 22 Aug 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-2025-38633 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-2025-38633/ (Markdown: https://insights.sbomify.com/CVE-2025-38633/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38633
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38633
- OSV: https://osv.dev/vulnerability/CVE-2025-38633

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38633/
Summaries are generated and may contain mistakes; the official description above is the record.