# CVE-2026-68405: wifi: mac80211: free AP_VLAN bc_buf SKBs outside IRQ lock

> A race condition in the Linux kernel Wi-Fi driver allows local attackers to trigger a kernel warning and potential denial of service by stopping an AP VLAN interface.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** BELL-CVE-2026-68405, DEBIAN-CVE-2026-68405, GHSA-qx36-wgrc-gggh, UBUNTU-CVE-2026-68405

## What is CVE-2026-68405?

CVE-2026-68405 is a vulnerability in Linux, published on 10 Aug 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: free AP_VLAN bc_buf SKBs outside IRQ lock

ieee80211_do_stop() removes AP_VLAN packets from the parent AP
ps->bc_buf while holding ps->bc_buf.lock with IRQs disabled. It then
calls ieee80211_free_txskb() before dropping the lock.

ieee80211_free_txskb() is not just a passive SKB release. For SKBs with
TX status state it can report a dropped frame through cfg80211/nl80211,
and that path can reach netlink tap transmit. This is the same reason
the pending queue cleanup in ieee80211_do_stop() already unlinks SKBs
under the queue lock and frees them after IRQ state is restored.

The buggy scenario involves two paths, with each column showing the
order within that path:

AP_VLAN management TX:             AP_VLAN stop:
1. attach ACK-status state         1. clear the running state
2. queue a multicast SKB on        2. take ps->bc_buf.lock with IRQs
   parent ps->bc_buf                  disabled
                                   3. unlink the AP_VLAN SKB
                                   4. call ieee80211_free_txskb()

Unlink matching AP_VLAN SKBs from ps->bc_buf under the existing lock,
but move them to a local free queue. Drop the lock and restore IRQ state
before calling ieee80211_free_txskb().

WARNING: kernel/softirq.c:430 at __local_bh_enable_ip

## Which versions are affected by CVE-2026-68405?


## How do I fix CVE-2026-68405?

Apply the vendor's patch.

## Is CVE-2026-68405 being exploited?

There is no known exploitation of CVE-2026-68405 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68405 and fix it if it is affected.

What it is: CVE-2026-68405 is a vulnerability in Linux, published on 10 Aug 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-2026-68405 in the wild and no public exploit code.

Affected product: Linux. 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-2026-68405/ (Markdown: https://insights.sbomify.com/CVE-2026-68405/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68405
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68405
- OSV: https://osv.dev/vulnerability/CVE-2026-68405

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68405/
Summaries are generated and may contain mistakes; the official description above is the record.