Vulnerability · Published Apr 22, 2026 · Assigned by freebsd

CVE-2026-5398Kernel use-after-free bug in the TIOCNOTTY handler

High 8.4

In plain English

A high-severity use-after-free in FreeBSD from FreeBSD. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 11% of all known vulnerabilities).

Severity (CVSS 3.1)8.4High

Exploit odds (30 days)0.2%top 89.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

The implementation of TIOCNOTTY failed to clear a back-pointer from the structure representing the controlling terminal to the calling process' session. If the invoking process then exits, the terminal structure may end up containing a pointer to freed memory. A malicious process can abuse the dangling pointer to grant itself root privileges.

Affected products (as reported)

Vendor	Product	Versions
FreeBSD	FreeBSD	15.0-RELEASE – before p614.4-RELEASE – before p214.3-RELEASE – before p1113.5-RELEASE – before p12

Weakness: CWE-416 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

https://security.freebsd.org/advisories/FreeBSD-SA-26:10.tty.asc vendor-advisory