CVE-2026-58093

Kernel use-after-free via tty ioctls

State: Published
Severity: 7.0 High
Published: Aug 26, 2026
Updated: Aug 27, 2026
Reserved: Jun 29, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	7.0 High	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H	CISA-ADP

Weaknesses

CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CWE-416 Use After Free

Affected Products

Product	Versions
FreeBSDFreeBSD	15.1-RELEASE to before p3Affected 15.0-RELEASE to before p13Affected 14.4-RELEASE to before p9Affected

References

https://security.freebsd.org/advisories/FreeBSD-SA-26:62.tty.ascvendor-advisory

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