CVE-2026-80735 ovpn: ensure socket is owned by ovpn before deref sk_user_data
A missing check in the Linux kernel OVPN module allows out-of-bounds reads when sockets are shared with other subsystems like BPF SOCKMAP.
- 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-2026-80735?
CVE-2026-80735 is a high-severity memory corruption vulnerability in Linux, published on 3 Sep 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:
ovpn: ensure socket is owned by ovpn before deref sk_user_data
Some subsystems, like BPF SOCKMAP, set sk_user_data without actually setting the encap_type.
For this reason, we must make sure that the type is the one ovpn expects before dereferencing sk_user_data.
Failing to do so may lead to out-of-bounds reads.
Which versions are affected by CVE-2026-80735?
How do I fix CVE-2026-80735?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-80735 being exploited?
There is no known exploitation of CVE-2026-80735 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-80735, DEBIAN-CVE-2026-80735, GHSA-2h35-47m3-h9hp, UBUNTU-CVE-2026-80735.