# CVE-2026-93067: drm/bridge: tc358767: clamp the reported AUX read size to the request

> A buffer overflow in the Linux kernel tc358767 DRM bridge driver allows local attackers to execute code or cause a denial of service via crafted AUX transfers.

- **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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-102731, BELL-CVE-2026-93067, DEBIAN-CVE-2026-93067, GHSA-wpcc-v879-hj4w, UBUNTU-CVE-2026-93067

## What is CVE-2026-93067?

CVE-2026-93067 is a memory corruption vulnerability in Linux, published on 17 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/bridge: tc358767: clamp the reported AUX read size to the request

tc_aux_transfer() clamps an AUX read to the payload limit:

	size_t size = min_t(size_t, DP_AUX_MAX_PAYLOAD_BYTES - 1, msg->size);

After the transfer it replaces size with the byte count the controller
reports in AUX_BYTES:

	if (size)
		size = FIELD_GET(AUX_BYTES, auxstatus);

AUX_BYTES is GENMASK(15, 8), so it can be up to 255. Nothing clamps it
back to the request. tc_aux_read_data() reads that many bytes into the
16-byte auxrdata stack buffer, then copies them into the caller buffer. A
reported count of 255 makes the read run to 256 bytes and overruns both.

The controller should never report more than it was asked to transfer, so
this is defense in depth rather than a live hole. The reported count is
only lightly trusted, and the check is cheap. Clamp it back to the request,
the same way ti-sn65dsi86 does in commit aca58eac52b8 ("drm/bridge:
ti-sn65dsi86: Never store more than msg->size bytes in AUX xfer").

## Which versions are affected by CVE-2026-93067?


## How do I fix CVE-2026-93067?

Apply the vendor's patch.

## Is CVE-2026-93067 being exploited?

There is no known exploitation of CVE-2026-93067 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93067 and fix it if it is affected.

What it is: CVE-2026-93067 is a memory corruption vulnerability in Linux, published on 17 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-2026-93067 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-2026-93067/ (Markdown: https://insights.sbomify.com/CVE-2026-93067/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93067
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93067
- OSV: https://osv.dev/vulnerability/CVE-2026-93067

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93067/
Summaries are generated and may contain mistakes; the official description above is the record.