# CVE-2025-71140: media: mediatek: vcodec: Use spinlock for context list protection lock

> A NULL pointer dereference in the MediaTek vcodec driver can cause a kernel crash when triggered by specific video decoding operations.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 14 Jan 2026
- **Updated:** 27 May 2026
- **Also known as:** DEBIAN-CVE-2025-71140, GHSA-fmmj-6v74-3cm2, ROOT-OS-DEBIAN-13-CVE-2025-71140, ROOT-OS-UBUNTU-2404-CVE-2025-71140, UBUNTU-CVE-2025-71140

## What is CVE-2025-71140?

CVE-2025-71140 is a vulnerability in Linux, published on 14 Jan 2026. 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:

media: mediatek: vcodec: Use spinlock for context list protection lock

Previously a mutex was added to protect the encoder and decoder context
lists from unexpected changes originating from the SCP IP block, causing
the context pointer to go invalid, resulting in a NULL pointer
dereference in the IPI handler.

Turns out on the MT8173, the VPU IPI handler is called from hard IRQ
context. This causes a big warning from the scheduler. This was first
reported downstream on the ChromeOS kernels, but is also reproducible
on mainline using Fluster with the FFmpeg v4l2m2m decoders. Even though
the actual capture format is not supported, the affected code paths
are triggered.

Since this lock just protects the context list and operations on it are
very fast, it should be OK to switch to a spinlock.

## Which versions are affected by CVE-2025-71140?


## How do I fix CVE-2025-71140?

Apply the vendor's patch.

## Is CVE-2025-71140 being exploited?

There is no known exploitation of CVE-2025-71140 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-71140 and fix it if it is affected.

What it is: CVE-2025-71140 is a vulnerability in Linux, published on 14 Jan 2026. 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-2025-71140 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-2025-71140/ (Markdown: https://insights.sbomify.com/CVE-2025-71140/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-71140
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-71140
- OSV: https://osv.dev/vulnerability/CVE-2025-71140

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-71140/
Summaries are generated and may contain mistakes; the official description above is the record.