Simple Machines Forum (SMF) 2.0.6, 1.1.19, and earlier allows remote attackers to impersonate arbitrary users via a Unicode homoglyph character in a username.
Simple Machines Forum (SMF) before 1.1.19 and 2.x before 2.0.6 allows remote attackers to impersonate arbitrary users via multiple space characters characters.
Simple Machines Forum (SMF) before 1.1.19 and 2.x before 2.0.6 allows remote attackers to conduct clickjacking attacks via an X-Frame-Options header.