# CVE-2026-64574: wifi: mac80211: tear down new links on vif update error path

> A use-after-free in the Linux kernel mac80211 subsystem allows local attackers to trigger a crash or potentially execute code via debugfs access after a link update failure.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 5 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-94467, BELL-CVE-2026-64574, DEBIAN-CVE-2026-64574, GHSA-5g36-vffc-3jvc, UBUNTU-CVE-2026-64574

## What is CVE-2026-64574?

CVE-2026-64574 is a high-severity use after free vulnerability in Linux, published on 5 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: tear down new links on vif update error path

When ieee80211_vif_update_links() adds new links it allocates a link
container for each and calls ieee80211_link_init() (which registers the
per-link debugfs files with file->private_data pointing into the container)
and ieee80211_link_setup(). If the subsequent drv_change_vif_links() fails,
the error path restores the old pointers and jumps to 'free', which frees
the new containers but never removes their debugfs entries or stops the
links. The debugfs files survive with file->private_data dangling at the
freed container, so a later open()+read() (e.g. link-1/txpower)
dereferences freed memory in ieee80211_if_read_link(), a use-after-free.

The removal path already dismantles links correctly via
ieee80211_tear_down_links(), which removes each link's keys and debugfs
entries and calls ieee80211_link_stop(); the add path on the error branch
does not. Commit be1ba9ed221f ("wifi: mac80211: avoid weird state in error
path") hardened this same error path for the link-removal case
(new_links == 0) but left the newly-added links' teardown unaddressed.

drv_change_vif_links() can fail at runtime on MLO drivers (internal
allocation / queue / firmware command failures).

Remove the new links' debugfs entries and stop them before freeing.

  BUG: KASAN: slab-use-after-free in ieee80211_if_read_link (net/mac80211/debugfs_netdev.c:127)
  Read of size 8 at addr ffff888011290000 by task exploit/145
  Call Trace:
   ...
   ieee80211_if_read_link (net/mac80211/debugfs_netdev.c:127)
   short_proxy_read (fs/debugfs/file.c:373)
   vfs_read (fs/read_write.c:572)
   ksys_read (fs/read_write.c:716)
   do_syscall_64 (arch/x86/entry/syscall_64.c:94)
   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
  ...
  Oops: general protection fault, probably for non-canonical address 0xdffffc000000000a
  RIP: 0010:ieee80211_if_read_link (net/mac80211/debugfs_netdev.c:127)
  Kernel panic - not syncing: Fatal exception

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-64574?


## How do I fix CVE-2026-64574?

Apply the vendor's patch.

## Is CVE-2026-64574 being exploited?

There is no known exploitation of CVE-2026-64574 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64574 and fix it if it is affected.

What it is: CVE-2026-64574 is a high-severity use after free vulnerability in Linux, published on 5 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-2026-64574 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-2026-64574/ (Markdown: https://insights.sbomify.com/CVE-2026-64574/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64574
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64574
- OSV: https://osv.dev/vulnerability/CVE-2026-64574

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64574/
Summaries are generated and may contain mistakes; the official description above is the record.