---
id: CVE-2026-23279
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  wifi: mac80211: fix NULL pointer dereference in mesh_rx_csa_frame()

  In mesh_rx_csa_frame(), elems->mesh_chansw_params_ie is dereferenced
  at lines 1638 and 1642 without…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  wifi: mac80211: fix NULL pointer dereference in mesh_rx_csa_frame()

  In mesh_rx_csa_frame(), elems->mesh_chansw_params_ie is dereferenced
  at lines 1638 and 1642 without…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-476
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 3.13, < 5.10.253'
  - 'linux_kernel >= 5.11, < 5.15.203'
  - 'linux_kernel >= 5.16, < 6.1.167'
  - 'linux_kernel >= 6.2, < 6.6.130'
  - 'linux_kernel >= 6.7, < 6.12.77'
  - 'linux_kernel >= 6.13, < 6.18.17'
  - 'linux_kernel >= 6.19, < 6.19.7'
  - linux_kernel = 7.0
patched:
  - linux_kernel 6.19.7
published: '2026-03-25'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T02:18:46.597'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-23279'
references:
  - url: 'https://git.kernel.org/stable/c/017c1792525064a723971f0216e6ef86a8c7af11'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/22a9adea7e26d236406edc0ea00b54351dd56b9c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2b5f282b1b7241ef624c3399a1cdff0bb1a3eeab'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/753ad20dcbe36b67088c7770d8fc357d7cc43e08'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/be8b82c567fda86f2cbb43b7208825125bb31421'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cc6d5a3c0a854aeae00915fc5386570c86029c60'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f061336f072ab03fd29270ae61fede46bf8fd69d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f5d8af683410a8c82e48b51291915bd612523d9a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-784472.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00136
epssPercentile: 0.02685
ingestedAt: '2026-10-15T03:30:12.838Z'
---

## Overview

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

wifi: mac80211: fix NULL pointer dereference in mesh_rx_csa_frame()

In mesh_rx_csa_frame(), elems->mesh_chansw_params_ie is dereferenced
at lines 1638 and 1642 without a prior NULL check:

    ifmsh->chsw_ttl = elems->mesh_chansw_params_ie->mesh_ttl;
    ...
    pre_value = le16_to_cpu(elems->mesh_chansw_params_ie->mesh_pre_value);

The mesh_matches_local() check above only validates the Mesh ID,
Mesh Configuration, and Supported Rates IEs.  It does not verify the
presence of the Mesh Channel Switch Parameters IE (element ID 118).
When a received CSA action frame omits that IE, ieee802_11_parse_elems()
leaves elems->mesh_chansw_params_ie as NULL, and the unconditional
dereference causes a kernel NULL pointer dereference.

A remote mesh peer with an established peer link (PLINK_ESTAB) can
trigger this by sending a crafted SPECTRUM_MGMT/CHL_SWITCH action frame
that includes a matching Mesh ID and Mesh Configuration IE but omits the
Mesh Channel Switch Parameters IE.  No authentication beyond the default
open mesh peering is required.

Crash confirmed on kernel 6.17.0-5-generic via mac80211_hwsim:

  BUG: kernel NULL pointer dereference, address: 0000000000000000
  Oops: Oops: 0000 [#1] SMP NOPTI
  RIP: 0010:ieee80211_mesh_rx_queued_mgmt+0x143/0x2a0 [mac80211]
  CR2: 0000000000000000

Fix by adding a NULL check for mesh_chansw_params_ie after
mesh_matches_local() returns, consistent with how other optional IEs
are guarded throughout the mesh code.

The bug has been present since v3.13 (released 2014-01-19).

## Affected

- `linux_kernel >= 3.13, < 5.10.253`
- `linux_kernel >= 5.11, < 5.15.203`
- `linux_kernel >= 5.16, < 6.1.167`
- `linux_kernel >= 6.2, < 6.6.130`
- `linux_kernel >= 6.7, < 6.12.77`
- `linux_kernel >= 6.13, < 6.18.17`
- `linux_kernel >= 6.19, < 6.19.7`
- `linux_kernel = 7.0`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.19.7`