# CVE-2026-68193: wifi: mt76: mt7925: drop TXRX_NOTIFY on non-mmio buses

> A null pointer dereference in the mt7925 WiFi driver causes a kernel crash when processing specific packets on USB buses, leading to denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-68193, DEBIAN-CVE-2026-68193, GHSA-wvcm-cfhx-9mp7, UBUNTU-CVE-2026-68193

## What is CVE-2026-68193?

CVE-2026-68193 is a vulnerability in Linux, published on 10 Aug 2026. 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:

wifi: mt76: mt7925: drop TXRX_NOTIFY on non-mmio buses

PKT_TYPE_TXRX_NOTIFY is an mmio-only event, but mt7925_rx_check() and
mt7925_queue_rx_skb() dispatch it to mt7925_mac_tx_free() on every bus.
mt7925_mac_tx_free() cleans the DMA tx queues with
mt76_queue_tx_cleanup(), which calls queue_ops->tx_cleanup(). Only the
mmio queue ops implement that callback; on USB it is NULL, so a
TXRX_NOTIFY there calls a NULL pointer in the RX worker:

  BUG: kernel NULL pointer dereference, address: 0000000000000000
  RIP: 0010:0x0
  Call Trace:
   mt7925_mac_tx_free+0x58/0x350 [mt7925_common]
   mt7925_rx_check+0xe2/0x130 [mt7925_common]
   mt76u_rx_worker+0x1b9/0x620 [mt76_usb]

Drop the event on non-mmio buses via mt76_is_mmio(), as in
commit 5683e1488aa9 ("wifi: mt76: connac: do not check WED status for
non-mmio devices").

## Which versions are affected by CVE-2026-68193?


## How do I fix CVE-2026-68193?

Apply the vendor's patch.

## Is CVE-2026-68193 being exploited?

There is no known exploitation of CVE-2026-68193 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68193 and fix it if it is affected.

What it is: CVE-2026-68193 is a vulnerability in Linux, published on 10 Aug 2026. 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-2026-68193 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-2026-68193/ (Markdown: https://insights.sbomify.com/CVE-2026-68193/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68193
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68193
- OSV: https://osv.dev/vulnerability/CVE-2026-68193

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68193/
Summaries are generated and may contain mistakes; the official description above is the record.