# CVE-2026-89817: drm/gud: NUL-terminate TV mode names read from the device

> A missing null termination in the Linux kernel DRM gud driver allows reading out-of-bounds memory or causing a crash when processing TV mode names from a USB device.

- **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:** 16 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-101306, BELL-CVE-2026-89817, DEBIAN-CVE-2026-89817, GHSA-g57w-mh9m-gp2m, UBUNTU-CVE-2026-89817

## What is CVE-2026-89817?

CVE-2026-89817 is a vulnerability in Linux, published on 16 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:

drm/gud: NUL-terminate TV mode names read from the device

gud_connector_add_tv_mode() reads a buffer of fixed-size mode names from
the USB device and passes pointers into it to
drm_mode_create_tv_properties_legacy(), which calls strlen() on each one.
Nothing guarantees the device NUL-terminates a name, so strlen() can run
past the end of a slot and, for the last mode, past the end of the
allocation.

Terminate each name at the end of its slot before use.

## Which versions are affected by CVE-2026-89817?


## How do I fix CVE-2026-89817?

Apply the vendor's patch.

## Is CVE-2026-89817 being exploited?

There is no known exploitation of CVE-2026-89817 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89817 and fix it if it is affected.

What it is: CVE-2026-89817 is a vulnerability in Linux, published on 16 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-2026-89817 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-2026-89817/ (Markdown: https://insights.sbomify.com/CVE-2026-89817/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89817
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89817
- OSV: https://osv.dev/vulnerability/CVE-2026-89817

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89817/
Summaries are generated and may contain mistakes; the official description above is the record.