On BIG-IP versions 16.0.x before 16.0.1.1, 15.1.x before 15.1.2.1, 14.1.x before 14.1.4, 13.1.x before 13.1.3.6, 12.1.x before 12.1.5.3, and 11.6.x before 11.6.5.3, undisclosed endpoints in iControl REST allow for a reflected XSS attack, which could lead to a complete compromise of the BIG-IP system if the victim user is granted the admin role. This vulnerability is due to an incomplete fix for CVE-2020-5948. Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.