CVE-2026-74750 ovpn: defer key slot crypto freeing to workqueue
A race condition in the Linux kernel's ovpn module allows unsafe memory freeing, potentially causing a system crash or denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74750?
CVE-2026-74750 is a high-severity vulnerability in Linux, published on 26 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ovpn: defer key slot crypto freeing to workqueue
Key slots are released through a kref and the existing release path frees the AEAD transforms from an RCU callback. That is not safe for all crypto implementations: crypto_free_aead can sleep, for example when an async or hardware implementation has teardown work to complete.
Use queue_rcu_work for key-slot release. This keeps the RCU grace period needed by lockless key-slot readers, but runs the actual crypto teardown from workqueue context where sleeping is allowed. Once the rcu_work callback runs, pre-existing RCU readers are gone, and the final kref put already proves that no transform user remains, so the worker can release the AEAD transforms and free the slot directly.
The previous patch drains ovpn_wq during module exit, so queued key-slot teardown work cannot outlive module text.
Which versions are affected by CVE-2026-74750?
How do I fix CVE-2026-74750?
Apply the vendor's patch.
Is CVE-2026-74750 being exploited?
There is no known exploitation of CVE-2026-74750 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74750, DEBIAN-CVE-2026-74750, GHSA-2495-48wf-cqx2, UBUNTU-CVE-2026-74750.