CVE-2026-58093 Kernel use-after-free via tty ioctls
An unprivileged local user can exploit a race condition in the TIOCSCTTY ioctl handler to escalate privileges on FreeBSD systems.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-58093?
CVE-2026-58093 is a high-severity use after free vulnerability in Freebsd Freebsd, published on 26 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
The TIOCSCTTY ioctl handler drops the tty lock in order to acquire the process tree lock. After reacquiring the tty lock, the handler did not revalidate the state of the terminal, and could proceed to link a terminal that was concurrently being destroyed to the calling process' session.
An unprivileged local user can exploit this race condition to escalate privileges.
Which versions are affected by CVE-2026-58093?
It affects 1 product.
Products include Freebsd Freebsd.
How do I fix CVE-2026-58093?
No fix has been published for CVE-2026-58093 yet. Limit exposure of the affected software until one is available.
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-2026-58093 being exploited?
There is no known exploitation of CVE-2026-58093 in the wild and no public exploit code.