# CVE-2026-90422: clk: mediatek: pllfh: Fix IO remapping leak in register_pllfhs error path

> A memory leak in the MediaTek PLL clock driver error path can lead to resource exhaustion and denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Not stated
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-110438, BELL-CVE-2026-90422, DEBIAN-CVE-2026-90422, GHSA-hw67-72fp-vf5f, UBUNTU-CVE-2026-90422

## What is CVE-2026-90422?

CVE-2026-90422 is a memory corruption vulnerability in Linux, published on 17 Sep 2026. 

### Official description

In the Linux kernel, the following vulnerability has been resolved:

clk: mediatek: pllfh: Fix IO remapping leak in register_pllfhs error path

When mtk_clk_register_pllfhs function fails to register a PLL, it
unregisters all PLLs and cleans up itself in its error path before
returning, so the function callers don't need to do it.

But contrary to mtk_clk_unregister_pllfhs function, that does almost
the same sequence, it does not free the IO memory mapped on fhctl node,
leading to a leak.

Fix this leak by factorizing the cleanup sequence in a new private
function and use it both mtk_clk_register_pllfhs and
mtk_clk_unregister_pllfhs functions.

Also, change the loop index start value to avoid the -1 operation on
index at each loop.

## Which versions are affected by CVE-2026-90422?


## How do I fix CVE-2026-90422?

Apply the vendor's patch.

## Is CVE-2026-90422 being exploited?

There is no known exploitation of CVE-2026-90422 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90422 and fix it if it is affected.

What it is: CVE-2026-90422 is a memory corruption vulnerability in Linux, published on 17 Sep 2026. 
Exploitation: There is no known exploitation of CVE-2026-90422 in the wild and no public exploit code.

Affected product: Linux. 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-2026-90422/ (Markdown: https://insights.sbomify.com/CVE-2026-90422/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90422
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90422
- OSV: https://osv.dev/vulnerability/CVE-2026-90422

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90422/
Summaries are generated and may contain mistakes; the official description above is the record.