Cross-site scripting (XSS) vulnerability in Six Apart (formerly Six Apart KK) Movable Type (MT) Pro 5.13 allows remote attackers to inject arbitrary web script or HTML via the comment section.
Improper Neutralization of Input During Web Page Generation The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.