CVE-2026-46238 batman-adv: stop caching unowned originator pointers in BAT IV
A use-after-free vulnerability in the Linux kernel's batman-adv module allows attackers to potentially execute code or cause a system crash.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-46238?
CVE-2026-46238 is a high-severity use after free vulnerability in Linux kernel, published on 28 May 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: stop caching unowned originator pointers in BAT IV
BAT IV keeps the last-hop neighbor address in each neigh_node, but some paths also cache an originator pointer derived from a temporary lookup. That pointer is not owned by the neigh_node and may no longer refer to a live originator entry after purge handling runs.
Stop storing the auxiliary originator pointer in the BAT IV neighbor state. When BAT IV needs the neighbor originator data, resolve it from the stored neighbor address and drop the reference again after use.
[sven: avoid bonding logic for outgoing OGM]
Which versions are affected by CVE-2026-46238?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-46238?
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-2026-46238 being exploited?
There is no known exploitation of CVE-2026-46238 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-88875, BELL-CVE-2026-46238, DEBIAN-CVE-2026-46238, GHSA-vhmf-xjjg-5pxr, ROOT-OS-DEBIAN-11-CVE-2026-46238, ROOT-OS-DEBIAN-12-CVE-2026-46238 and 3 more.