# CVE-2026-23279: wifi: mac80211: fix NULL pointer dereference in mesh_rx_csa_frame()

> A remote attacker can cause a kernel crash by sending a crafted mesh action frame that triggers a NULL pointer dereference in the mac80211 subsystem.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Mar 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-80744, BELL-CVE-2026-23279, DEBIAN-CVE-2026-23279, GHSA-3969-jvq7-cjf4, ROOT-OS-DEBIAN-11-CVE-2026-23279, ROOT-OS-DEBIAN-12-CVE-2026-23279, ROOT-OS-DEBIAN-13-CVE-2026-23279, ROOT-OS-UBUNTU-2204-CVE-2026-23279, ROOT-OS-UBUNTU-2404-CVE-2026-23279, UBUNTU-CVE-2026-23279

## What is CVE-2026-23279?

CVE-2026-23279 is a medium-severity vulnerability in Linux kernel, published on 25 Mar 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: 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).

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-23279?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23279?

Apply the vendor's patch.

## Is CVE-2026-23279 being exploited?

There is no known exploitation of CVE-2026-23279 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23279 and fix it if it is affected.

What it is: CVE-2026-23279 is a medium-severity vulnerability in Linux kernel, published on 25 Mar 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-2026-23279 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-23279/ (Markdown: https://insights.sbomify.com/CVE-2026-23279/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23279
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23279
- OSV: https://osv.dev/vulnerability/CVE-2026-23279

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23279/
Summaries are generated and may contain mistakes; the official description above is the record.