# CVE-2026-74698: net/mlx5e: fix BQL reset on SQ re-activation

> A bug in the Linux kernel mlx5e driver causes a kernel panic during TX queue re-activation, leading to a denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Aug 2026
- **Updated:** 22 Aug 2026
- **Also known as:** BELL-CVE-2026-74698, DEBIAN-CVE-2026-74698, GHSA-qrj3-pxvx-pgch, UBUNTU-CVE-2026-74698

## What is CVE-2026-74698?

CVE-2026-74698 is a denial of service vulnerability in Linux, published on 22 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

net/mlx5e: fix BQL reset on SQ re-activation

mlx5e_queue_start() deactivates and re-activates all channels but closes
only the queue being restarted. mlx5e_activate_txqsq() then
unconditionally calls netdev_tx_reset_queue(), zeroing the BQL counters
of channels that kept their in-flight TX WQEs. The next completion then
over-charges and trips the BUG_ON() in dql_completed():

  kernel BUG at lib/dynamic_queue_limits.c:99!
  RIP: 0010:dql_completed+0x23d/0x280
  Call Trace:
   <IRQ>
   mlx5e_poll_tx_cq+0x668/0xa60
   mlx5e_napi_poll+0x5b/0x7b0
   net_rx_action+0x15a/0x580

Reset BQL only when the SQ has no bytes in flight (sq->cc == sq->pc).

In the case that reset is skipped, the outstanding WQEs will eventually
complete and rebalance the dql. The dql->limit is carried across the
reset.

## Which versions are affected by CVE-2026-74698?


## How do I fix CVE-2026-74698?

Apply the vendor's patch.

## Is CVE-2026-74698 being exploited?

There is no known exploitation of CVE-2026-74698 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74698 and fix it if it is affected.

What it is: CVE-2026-74698 is a denial of service vulnerability in Linux, published on 22 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-74698 in the wild and no public exploit code.

Affected product: Linux. 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-2026-74698/ (Markdown: https://insights.sbomify.com/CVE-2026-74698/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74698
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74698
- OSV: https://osv.dev/vulnerability/CVE-2026-74698

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74698/
Summaries are generated and may contain mistakes; the official description above is the record.