CVE-2026-80753 ovpn: run deferred work on a module-owned workqueue
A use-after-free vulnerability in the Linux kernel ovpn module allows attackers to execute arbitrary code or cause a denial of service via race conditions during module unloading.
- 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-2026-80753?
CVE-2026-80753 is a high-severity use after free 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: run deferred work on a module-owned workqueue
ovpn queues several work items whose callbacks execute module text. These works currently run on the global system workqueues, so module exit has no driver-owned drain point that guarantees the callbacks have fully returned before the module text can be freed.
Object references protect the objects used by the callbacks, but they do not prove that a workqueue function has returned. In particular, a worker can drop the final reference that unblocks device teardown while it is still executing ovpn code.
Add a module-owned workqueue and queue all ovpn work items on it. During module exit, unregister rtnl and netlink first, flush the workqueue so ordinary ovpn workers finish, run the final RCU barrier, and destroy the workqueue last. This keeps the workqueue available for cleanup work queued from RCU callbacks, while ensuring no ovpn work item can outlive the module text.
The per-device delayed keepalive work remains explicitly disabled during netdev teardown (disable_delayed_work_sync in ndo_uninit), since flush_workqueue does not flush delayed work that is still only pending on its timer.
Which versions are affected by CVE-2026-80753?
How do I fix CVE-2026-80753?
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-2026-80753 being exploited?
There is no known exploitation of CVE-2026-80753 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-80753, DEBIAN-CVE-2026-80753, GHSA-v4xm-q8j7-q9wj, UBUNTU-CVE-2026-80753.