# CVE-2021-46931: net/mlx5e: Wrap the tx reporter dump callback to extract the sq

> A type confusion bug in the Mellanox mlx5 network driver causes a kernel stack overflow and panic during TX timeout recovery, leading to denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **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:** Yes
- **Published:** 27 Feb 2024
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2021-46931, GHSA-5gx7-f5j6-6r9q, UBUNTU-CVE-2021-46931

## What is CVE-2021-46931?

CVE-2021-46931 is a medium-severity memory corruption vulnerability in Linux kernel, published on 27 Feb 2024. 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/mlx5e: Wrap the tx reporter dump callback to extract the sq

Function mlx5e_tx_reporter_dump_sq() casts its void * argument to struct
mlx5e_txqsq *, but in TX-timeout-recovery flow the argument is actually
of type struct mlx5e_tx_timeout_ctx *.

 mlx5_core 0000:08:00.1 enp8s0f1: TX timeout detected
 mlx5_core 0000:08:00.1 enp8s0f1: TX timeout on queue: 1, SQ: 0x11ec, CQ: 0x146d, SQ Cons: 0x0 SQ Prod: 0x1, usecs since last trans: 21565000
 BUG: stack guard page was hit at 0000000093f1a2de (stack is 00000000b66ea0dc..000000004d932dae)
 kernel stack overflow (page fault): 0000 [#1] SMP NOPTI
 CPU: 5 PID: 95 Comm: kworker/u20:1 Tainted: G W OE 5.13.0_mlnx #1
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
 Workqueue: mlx5e mlx5e_tx_timeout_work [mlx5_core]
 RIP: 0010:mlx5e_tx_reporter_dump_sq+0xd3/0x180
 [mlx5_core]
 Call Trace:
 mlx5e_tx_reporter_dump+0x43/0x1c0 [mlx5_core]
 devlink_health_do_dump.part.91+0x71/0xd0
 devlink_health_report+0x157/0x1b0
 mlx5e_reporter_tx_timeout+0xb9/0xf0 [mlx5_core]
 ? mlx5e_tx_reporter_err_cqe_recover+0x1d0/0x1d0
 [mlx5_core]
 ? mlx5e_health_queue_dump+0xd0/0xd0 [mlx5_core]
 ? update_load_avg+0x19b/0x550
 ? set_next_entity+0x72/0x80
 ? pick_next_task_fair+0x227/0x340
 ? finish_task_switch+0xa2/0x280
   mlx5e_tx_timeout_work+0x83/0xb0 [mlx5_core]
   process_one_work+0x1de/0x3a0
   worker_thread+0x2d/0x3c0
 ? process_one_work+0x3a0/0x3a0
   kthread+0x115/0x130
 ? kthread_park+0x90/0x90
   ret_from_fork+0x1f/0x30
 --[ end trace 51ccabea504edaff ]---
 RIP: 0010:mlx5e_tx_reporter_dump_sq+0xd3/0x180
 PKRU: 55555554
 Kernel panic - not syncing: Fatal exception
 Kernel Offset: disabled
 end Kernel panic - not syncing: Fatal exception

To fix this bug add a wrapper for mlx5e_tx_reporter_dump_sq() which
extracts the sq from struct mlx5e_tx_timeout_ctx and set it as the
TX-timeout-recovery flow dump callback.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2021-46931?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-46931?

Apply the vendor's patch.

## Is CVE-2021-46931 being exploited?

There is no known exploitation of CVE-2021-46931 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-46931 and fix it if it is affected.

What it is: CVE-2021-46931 is a medium-severity memory corruption vulnerability in Linux kernel, published on 27 Feb 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-46931 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-46931/ (Markdown: https://insights.sbomify.com/CVE-2021-46931/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-46931
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-46931
- OSV: https://osv.dev/vulnerability/CVE-2021-46931

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-46931/
Summaries are generated and may contain mistakes; the official description above is the record.