On sites with Multi-Factor Authentication enabled, it was possible to use course self enrollment after passing only the first login factor (such as passing a username/password check). The user should also have to pass a second login factor before gaining access to self enrollment. Versions affected: 4.5 to 4.5.3, 4.4 to 4.4.7 and 4.3 to 4.3.11 Versions fixed: 4.5.4, 4.4.8 and 4.3.12