Kernel use-after-free via tty ioctls
FreeBSD-SA-26:62.tty · CVE-2026-58093
Our decision for FreeSense
FreeBSD corrected this on 2026-08-25, after the FreeBSD source pin of FreeSense 1.0 (pinned 2026-08-03). The fix arrives with the next FreeBSD pin of each line that is still updated. No one has checked yet whether FreeSense is exposed in practice.
- Advisory: corrected 2026-08-25
- FreeSense 1.0 pin: e004ff15f87e (2026-08-03)
- FreeSense 1.1 pin: a52c50b4b7c2 (2026-10-04)
- FreeSense 1.2 pin: a52c50b4b7c2 (2026-10-04)
By FreeSense version
| Version | Status | FreeBSD pin |
|---|---|---|
| FreeSense 1.01.0.7 · frozen, no further fixes | Open | 2026-08-03e004ff15 |
| FreeSense 1.11.1.9 | FixedFreeBSD pin of 2026-10-04 | 2026-10-04a52c50b4 |
| FreeSense 1.21.2.0-DEVELOPMENT | FixedFreeBSD pin of 2026-10-04 | 2026-10-04a52c50b4 |
Workaround
No workaround is available.
What FreeBSD says
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.
Impact
An unprivileged local user can exploit this race condition to escalate privileges.
Excerpt from the FreeBSD advisory. Read the original for the full text and the fix.