NamelessMC is a free, easy to use & powerful website software for Minecraft servers. In version 2.1.4 and prior, the forum allows users to post iframe elements inside forum topics/comments/feed with no restriction on the iframe's width and height attributes. This allows an authenticated attacker to perform a UI-based denial of service (DoS) by injecting oversized iframes that block the forum UI and disrupt normal user interactions. This issue has been patched in version 2.2.0.