# CVE-2026-64218: batman-adv: bla: fix report_work leak on backbone_gw purge

> A use-after-free vulnerability in the Linux kernel's batman-adv module allows attackers to cause memory corruption, potentially leading to code execution or system crashes.

- **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:** 24 Jul 2026
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2026-64218, DEBIAN-CVE-2026-64218, GHSA-jcwg-v5j7-jrrq, ROOT-OS-UBUNTU-2204-CVE-2026-64218, UBUNTU-CVE-2026-64218

## What is CVE-2026-64218?

CVE-2026-64218 is a high-severity use after free vulnerability in Linux kernel, published on 24 Jul 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:

batman-adv: bla: fix report_work leak on backbone_gw purge

batadv_bla_purge_backbone_gw() removes stale backbone gateway entries,
but fails to properly handle their associated report_work:

- If report_work is running, the purge must wait for it to finish before
  freeing the backbone_gw, otherwise the worker may access freed memory
  (e.g. bat_priv).
- If report_work is pending, the purge must cancel it and release the
  reference held for that pending work item.

The previous implementation called hlist_for_each_entry_safe() inside a
spin_lock_bh() section, but cancel_work_sync() may sleep and therefore
cannot be called from within a spinlock-protected region.

Restructure the loop to handle one entry per spinlock critical section:
acquire the lock, find the next entry to purge, remove it from the hash
list, then release the lock before calling cancel_work_sync() and
dropping the hash_entry reference. Repeat until no more entries require
purging.

## Which versions are affected by CVE-2026-64218?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-64218?

Apply the vendor's patch.

## Is CVE-2026-64218 being exploited?

There is no known exploitation of CVE-2026-64218 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-2026-64218 and fix it if it is affected.

What it is: CVE-2026-64218 is a high-severity use after free vulnerability in Linux kernel, published on 24 Jul 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-2026-64218 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-2026-64218/ (Markdown: https://insights.sbomify.com/CVE-2026-64218/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64218
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64218
- OSV: https://osv.dev/vulnerability/CVE-2026-64218

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64218/
Summaries are generated and may contain mistakes; the official description above is the record.