# CVE-2026-90379: wifi: mt76: mt7921: Add PCIe AER handler support to prevent system crash

> A missing validation in the mt7921 WiFi driver allows invalid memory access during PCIe AER errors, causing a system crash.

- **Severity:** High 8.8 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-101930, BELL-CVE-2026-90379, DEBIAN-CVE-2026-90379, GHSA-qfcx-6cpx-wgv3, UBUNTU-CVE-2026-90379

## What is CVE-2026-90379?

CVE-2026-90379 is a high-severity vulnerability in Linux, published on 17 Sep 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: mt7921: Add PCIe AER handler support to prevent system crash

When an AER error occurs and the bus is hung, the register reads return
0xFFFFFFFF, causing the DMA queue state to be corrupted and resulting in
an invalid memory access when accessing q->desc[] or q->entry[].

Unable to handle kernel paging request at virtual address
ffffffc01099eac0
pc : mt76_dma_add_buf+0x124/0x188 [mt76]
lr : mt76_dma_rx_fill+0x11c/0x1d8 [mt76]
sp : ffffffc016d9bbf0
x29: ffffffc016d9bc10 x28: 0000000000000000
x27: 0000000000000000 x26: ffffffb7855e50b8
x25: ffffffb80d04f000 x24: 0000000000000000
x23: 0000000000000ec0 x22: ffffffb796803648
x21: ffffffb796801f80 x20: ffffffb7968035f8
x19: 0000000000000ec0 x18: 0000000000000000
x17: 000000004ec00000 x16: 000000000ec00000
x15: ffffffc01099eac0 x14: 000000004ec00000
x13: 00000000ffc5a000 x12: ffffffc016d9bc32
x11: 00000000ffffffff x10: 0000000000000002
x9 : 0000000000000000 x8 : 000000000000b4ac
x7 : 0000000000000a20 x6 : ffffffb6c1806400
x5 : 0000000000000000 x4 : ffffffb80d04f000
x3 : 0000000000000000 x2 : 0000000000000001
x1 : 000000000ec04000 x0 : ffffffb7968035f8
Call trace:
 mt76_dma_add_buf+0x124/0x188 [mt76 (HASH:1029 4)]
 mt76_dma_rx_reset+0xe8/0xfc [mt76 (HASH:1029 4)]
 mt7921_wpdma_reset+0x188/0x1b0 [mt7921e (HASH:ee48 5)]
 mt7921e_mac_reset+0x128/0x418 [mt7921e (HASH:ee48 5)]
 mt7921_mac_reset_work+0xac/0x1a8 [mt7921_common (HASH:f721 6)]
 process_one_work+0x188/0x514
 worker_thread+0x12c/0x300
 kthread+0x140/0x1fc
 ret_from_fork+0x10/0x30

Fix the invalid memory access by validating the DMA index read from the
hardware before it is used as a queue index. An out-of-range value, such
as the 0xFFFFFFFF returned while the bus is hung, is now clamped so it can
no longer corrupt q->head or q->tail. In addition, check the bus_hung flag
in mt7921_mac_reset_work() before attempting the reset sequence, reject MCU
messages while the bus is hung, and install no-op bus operations when an
unrecoverable AER error is detected, preventing further invalid hardware
accesses.

Due to hardware limitations - such as the lack of a connected hardware
reset pin or the absence of host re-probe functionality - affected Wi-Fi
devices may not fully recover to a normal operational state after
certain errors, even with AER enabled.

## Which versions are affected by CVE-2026-90379?


## How do I fix CVE-2026-90379?

Apply the vendor's patch.

## Is CVE-2026-90379 being exploited?

There is no known exploitation of CVE-2026-90379 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90379 and fix it if it is affected.

What it is: CVE-2026-90379 is a high-severity vulnerability in Linux, published on 17 Sep 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-2026-90379 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-2026-90379/ (Markdown: https://insights.sbomify.com/CVE-2026-90379/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90379
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90379
- OSV: https://osv.dev/vulnerability/CVE-2026-90379

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90379/
Summaries are generated and may contain mistakes; the official description above is the record.