The FreeBSD Project has released an emergency security advisory (FreeBSD-SA-26:13.exec) addressing a critical local privilege escalation vulnerability in the execve() system call. The flaw, assigned CVE-2026-7270, affects all supported versions of FreeBSD including 13.x, 14.x, and 15.x branches.

The vulnerability stems from an operator precedence bug in the kernel that allows a buffer overflow to overwrite adjacent execve(2) argument buffers. According to the advisory credited to Ryan of Calif.io, an unprivileged user could exploit this to obtain superuser (root) privileges on affected systems. No workaround is available.

Administrators should update immediately using pkg(8) or freebsd-update(8), then reboot. Patches are available for stable/15, 14.4-STABLE, 13.5-STABLE, and their corresponding release branches. The fixes were deployed on April 29, 2026 across all supported FreeBSD versions.