# CVE-2026-23396: wifi: mac80211: fix NULL deref in mesh_matches_local()

> An adjacent attacker can crash the Linux kernel by sending a crafted mesh action frame, causing a denial of service.

- **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:** 26 Mar 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-80852, BELL-CVE-2026-23396, DEBIAN-CVE-2026-23396, GHSA-w4qg-rh8m-6c8q, ROOT-OS-DEBIAN-11-CVE-2026-23396, ROOT-OS-DEBIAN-12-CVE-2026-23396, ROOT-OS-DEBIAN-13-CVE-2026-23396, ROOT-OS-UBUNTU-2204-CVE-2026-23396, ROOT-OS-UBUNTU-2404-CVE-2026-23396, UBUNTU-CVE-2026-23396

## What is CVE-2026-23396?

CVE-2026-23396 is a medium-severity vulnerability in Linux kernel, published on 26 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 deref in mesh_matches_local()

mesh_matches_local() unconditionally dereferences ie->mesh_config to
compare mesh configuration parameters. When called from
mesh_rx_csa_frame(), the parsed action-frame elements may not contain a
Mesh Configuration IE, leaving ie->mesh_config NULL and triggering a
kernel NULL pointer dereference.

The other two callers are already safe:
  - ieee80211_mesh_rx_bcn_presp() checks !elems->mesh_config before
    calling mesh_matches_local()
  - mesh_plink_get_event() is only reached through
    mesh_process_plink_frame(), which checks !elems->mesh_config, too

mesh_rx_csa_frame() is the only caller that passes raw parsed elements
to mesh_matches_local() without guarding mesh_config. An adjacent
attacker can exploit this by sending a crafted CSA action frame that
includes a valid Mesh ID IE but omits the Mesh Configuration IE,
crashing the kernel.

The captured crash log:

Oops: general protection fault, probably for non-canonical address ...
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
Workqueue: events_unbound cfg80211_wiphy_work
[...]
Call Trace:
 <TASK>
 ? __pfx_mesh_matches_local (net/mac80211/mesh.c:65)
 ieee80211_mesh_rx_queued_mgmt (net/mac80211/mesh.c:1686)
 [...]
 ieee80211_iface_work (net/mac80211/iface.c:1754 net/mac80211/iface.c:1802)
 [...]
 cfg80211_wiphy_work (net/wireless/core.c:426)
 process_one_work (net/kernel/workqueue.c:3280)
 ? assign_work (net/kernel/workqueue.c:1219)
 worker_thread (net/kernel/workqueue.c:3352)
 ? __pfx_worker_thread (net/kernel/workqueue.c:3385)
 kthread (net/kernel/kthread.c:436)
 [...]
 ret_from_fork_asm (net/arch/x86/entry/entry_64.S:255)
 </TASK>

This patch adds a NULL check for ie->mesh_config at the top of
mesh_matches_local() to return false early when the Mesh Configuration
IE is absent.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-23396?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23396?

Apply the vendor's patch.

## Is CVE-2026-23396 being exploited?

There is no known exploitation of CVE-2026-23396 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-2026-23396 and fix it if it is affected.

What it is: CVE-2026-23396 is a medium-severity vulnerability in Linux kernel, published on 26 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-2026-23396 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-2026-23396/ (Markdown: https://insights.sbomify.com/CVE-2026-23396/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23396
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23396
- OSV: https://osv.dev/vulnerability/CVE-2026-23396

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23396/
Summaries are generated and may contain mistakes; the official description above is the record.