On BIG-IP 12.1.0-12.1.4.1, undisclosed requests can cause iControl REST processes to crash. The attack can only come from an authenticated user; all roles are capable of performing the attack. Unauthenticated users cannot perform this attack.
https://support.f5.com/csp/article/K22384173?utm_source=f5support&%3Butm_medium=RSS