# CVE-2026-93805: wifi: cfg80211: validate rx/tx MLME callback frame lengths before access

> A missing length validation in Linux kernel WiFi MLME callbacks allows out-of-bounds reads, potentially causing crashes or information disclosure.

- **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:** 24 Sep 2026
- **Updated:** 3 Oct 2026
- **Also known as:** AZL-103601, BELL-CVE-2026-93805, DEBIAN-CVE-2026-93805, GHSA-7vqv-hxrc-vvx2, UBUNTU-CVE-2026-93805

## What is CVE-2026-93805?

CVE-2026-93805 is a memory corruption vulnerability in Linux, published on 24 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: cfg80211: validate rx/tx MLME callback frame lengths before access

cfg80211_rx_mlme_mgmt() and cfg80211_tx_mlme_mgmt() call tracepoints
before rejecting frames shorter than the frame-control field. After
that, they only require len >= 2 before dispatching into subtype
handlers that assume their fixed fields are present.

The frames that trip this are not shorter than 2 bytes; they are short
relative to their subtype. mwifiex is a concrete in-tree example on the
length side: mwifiex_process_mgmt_packet() only requires a 4-address
ieee80211_hdr plus the 2-byte firmware length prefix before handing the
frame to cfg80211_rx_mlme_mgmt(). After stripping the length prefix and
removing addr4, pkt_len can be exactly 24: a bare 3-address management
header with no reason-code body. The existing WARN_ON(len < 2) does not
fire on such a frame, and cfg80211_process_deauth() then reads
u.deauth.reason_code as a two-byte access starting at offset 24,
immediately past the 24-byte buffer.

Add a frame-control length gate, then validate each subtype's minimum
frame size in an if/else-if chain that mirrors the dispatch logic. Trace
only after the frame is known to be well-formed.

Side effects of this change:
 - The WARN_ON(len < 2) is dropped. It only guarded the frame_control
   read, never the subtype fixed fields, and it does not fire on the
   frames that actually trigger the out-of-bounds read (which are >= 2).
   The len >= 2 check is kept as the guard before dereferencing
   frame_control, but without the warning: these are exported callbacks
   and a malformed frame from a driver should be dropped silently rather
   than backtraced.
 - cfg80211_tx_mlme_mgmt() previously routed every non-deauth subtype
   through disassociation handling; it now silently ignores unrecognised
   subtypes.

## Which versions are affected by CVE-2026-93805?


## How do I fix CVE-2026-93805?

Apply the vendor's patch.

## Is CVE-2026-93805 being exploited?

There is no known exploitation of CVE-2026-93805 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-93805 and fix it if it is affected.

What it is: CVE-2026-93805 is a memory corruption vulnerability in Linux, published on 24 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-2026-93805 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-2026-93805/ (Markdown: https://insights.sbomify.com/CVE-2026-93805/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-93805
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-93805
- OSV: https://osv.dev/vulnerability/CVE-2026-93805

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-93805/
Summaries are generated and may contain mistakes; the official description above is the record.