# CVE-2026-89724: media: vicodec: fix out-of-bounds write in FWHT encoder

> An out-of-bounds write in the Linux kernel vicodec driver allows attackers to corrupt kernel heap memory, potentially leading to code execution or privilege escalation.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-100483, BELL-CVE-2026-89724, DEBIAN-CVE-2026-89724, GHSA-8cqc-p4qr-2jqq, UBUNTU-CVE-2026-89724

## What is CVE-2026-89724?

CVE-2026-89724 is a high-severity memory corruption vulnerability in Linux, published on 11 Sep 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: vicodec: fix out-of-bounds write in FWHT encoder

vidioc_s_fmt_vid_out() sizes the encoder CAPTURE buffer from the
compressed descriptor pixfmt_fwht, whose sizeimage_mult is 3:
coded_w * coded_h * 3 + sizeof(struct fwht_cframe_hdr). fwht_encode_frame()
encodes one plane per component, and an incompressible plane takes the
FWHT_FRAME_UNENCODED path in encode_plane(), copying the plane verbatim.

For a 4-component pixel format all four planes are full resolution
(width_div == height_div == 1), so a frame that forces every plane
through the unencoded fallback writes
sizeof(struct fwht_cframe_hdr) + 4 * coded_w * coded_h bytes, overrunning
the plane by coded_w * coded_h, which can result in corruption
of adjacent kernel heap memory.

Bump pixfmt_fwht.sizeimage_mult from 3 to 4, matching the largest
components_num among the supported raw formats, so the capture buffer is
always large enough for the unencoded fallback.

## Which versions are affected by CVE-2026-89724?


## How do I fix CVE-2026-89724?

Apply the vendor's patch.

## Is CVE-2026-89724 being exploited?

There is no known exploitation of CVE-2026-89724 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89724 and fix it if it is affected.

What it is: CVE-2026-89724 is a high-severity memory corruption vulnerability in Linux, published on 11 Sep 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-2026-89724 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-2026-89724/ (Markdown: https://insights.sbomify.com/CVE-2026-89724/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89724
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89724
- OSV: https://osv.dev/vulnerability/CVE-2026-89724

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89724/
Summaries are generated and may contain mistakes; the official description above is the record.