---
id: "CVE-2026-98702"
kind: "vulnerability"
aliases: ["CVE-2026-98702"]
title: "Linux kernel: forged Wi-Fi channel switch frame can panic the system"
severity: "medium"
cvss: null
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["infrastructure", "kernel", "laptops", "linux", "mac80211", "servers", "wifi"]
not_affected_if: ["no-wifi-hardware", "panic-on-warn-disabled"]
published_at: "2026-10-18T16:17:23+00:00"
first_seen_at: "2026-10-23T21:57:16+00:00"
updated_at: "2026-10-25T05:18:53+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98702", "first_seen_at": "2026-10-23T21:57:16+00:00"}]
---

# Linux kernel: forged Wi-Fi channel switch frame can panic the system

A malformed 320 MHz channel switch announcement in a received Wi-Fi frame, on a link that does not support that width, leaves a value uninitialized in the mac80211 wireless stack. With panic_on_warn enabled, a nearby device sending that frame can crash the kernel.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run `uname -r` and compare with the fixed kernel versions in the upstream commit, which the sources do not list.
- Check whether `panic_on_warn` is set: `sysctl kernel.panic_on_warn` (unknown whether default configs enable it).
- Check whether the machine uses a mac80211 Wi-Fi driver: `lsmod | grep mac80211`.

## Fix

- Update the Linux kernel to a release that includes the mac80211 fix (version unknown from the sources).
- Until then, keep `kernel.panic_on_warn` at `0` if the machine does not need it.

## Timeline

- 2026-10-23T21:57:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98702

## From the sources

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

wifi: mac80211: reject invalid 320 MHz CSA bandwidth

The HT/VHT channel definition validator can receive a 320 MHz
bandwidth indication from a received CSA frame on a non-6 GHz link.
It warns for this unsupported width but continues with an uninitialized
vht_operation.chan_width, which is then read by
ieee80211_chandef_vht_oper(). With panic_on_warn enabled, this lets a
received frame panic the kernel.

Reject the channel definition before entering the VHT operation
conversion. This preserves the existing CSA fallback while avoiding
both the warning and the uninitialized read.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_