Use-after-free in FreeBSD - CVE-2026-5398
Published: April 22, 2026
Vulnerability identifier: #VU126824
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-5398
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: FreeBSD Foundation
Affected software:
FreeBSD
FreeBSD
Detailed vulnerability description
The vulnerability allows a local user to escalate privileges.
The vulnerability exists due to use-after-free in the TIOCNOTTY handler when processing the TIOCNOTTY ioctl operation. A local user can invoke the ioctl and then exit the process to escalate privileges.
Unprivileged processes may use this ioctl.
How to mitigate CVE-2026-5398
Install security update from vendor's website.