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.
- 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
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 include Linux kernel.
How do I fix CVE-2026-64218?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
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
Sources
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.