Cross-site scripting vulnerability in Movable Type series (Movable Type 7 r.4603 and earlier (Movable Type 7), Movable Type 6.5.2 and earlier (Movable Type 6.5), Movable Type Advanced 7 r.4603 and earlier (Movable Type Advanced 7), Movable Type Advanced 6.5.2 and earlier (Movable Type Advanced 6.5), Movable Type Premium 1.26 and earlier (Movable Type Premium), and Movable Type Premium Advanced 1.26 and earlier (Movable Type Premium Advanced)) allows remote attackers to inject arbitrary web script or HTML in the block editor and the rich text editor via a specially crafted URL.