Invision Community (aka IPS Community Suite or IP-Board) before 4.6.5.1 allows stored XSS, with resultant code execution, because an uploaded file can be placed in an IFRAME element within user-generated content. For code execution, the attacker can rely on the ability of an admin to install widgets, disclosure of the admin session ID in a Referer header, and the ability of an admin to use the templating engine (e.g., Edit HTML).
CWE-79