CVE-2025-21662 net/mlx5: Fix variable not being completed when function returns
A bug in the mlx5 network driver causes kernel tasks to hang indefinitely when command allocation fails, leading to a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-21662?
CVE-2025-21662 is a medium-severity denial of service vulnerability in Linux kernel, published on 21 Jan 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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
Which versions are affected by CVE-2025-21662?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-21662?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-21662 being exploited?
There is no known exploitation of CVE-2025-21662 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-21662, DEBIAN-CVE-2025-21662, GHSA-2ww6-2gwx-v942, UBUNTU-CVE-2025-21662.