# CVE-2026-31690: firmware: thead: Fix buffer overflow and use standard endian macros

> A buffer overflow in the TH1520 AON firmware protocol driver allows attackers to potentially execute arbitrary code or cause a system crash.

- **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:** 27 Apr 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2026-31690, DEBIAN-CVE-2026-31690, GHSA-3j3v-v8vh-9mw9, UBUNTU-CVE-2026-31690

## What is CVE-2026-31690?

CVE-2026-31690 is a high-severity memory corruption vulnerability in Linux kernel, published on 27 Apr 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:

firmware: thead: Fix buffer overflow and use standard endian macros

Addresses two issues in the TH1520 AON firmware protocol driver:

1. Fix a potential buffer overflow where the code used unsafe pointer
   arithmetic to access the 'mode' field through the 'resource' pointer
   with an offset. This was flagged by Smatch static checker as:
   "buffer overflow 'data' 2 <= 3"

2. Replace custom RPC_SET_BE* and RPC_GET_BE* macros with standard
   kernel endianness conversion macros (cpu_to_be16, etc.) for better
   portability and maintainability.

The functionality was re-tested with the GPU power-up sequence,
confirming the GPU powers up correctly and the driver probes
successfully.

[   12.702370] powervr ffef400000.gpu: [drm] loaded firmware
powervr/rogue_36.52.104.182_v1.fw
[   12.711043] powervr ffef400000.gpu: [drm] FW version v1.0 (build
6645434 OS)
[   12.719787] [drm] Initialized powervr 1.0.0 for ffef400000.gpu on
minor 0

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-31690?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31690?

Apply the vendor's patch.

## Is CVE-2026-31690 being exploited?

There is no known exploitation of CVE-2026-31690 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-31690 and fix it if it is affected.

What it is: CVE-2026-31690 is a high-severity memory corruption vulnerability in Linux kernel, published on 27 Apr 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-2026-31690 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-31690/ (Markdown: https://insights.sbomify.com/CVE-2026-31690/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31690
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31690
- OSV: https://osv.dev/vulnerability/CVE-2026-31690

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31690/
Summaries are generated and may contain mistakes; the official description above is the record.