vBulletin is prone to multiple HTML-injection vulnerabilities because it fails to properly sanitize user-supplied input before using it in dynamically generated content.
Successful exploits will allow attacker-supplied HTML and script code to run in the context of the affected browser, potentially allowing the attacker to steal cookie-based authentication credentials or control how the site is rendered to the user. Other attacks are also possible.
vBulletin versions 4.1.4 through 4.1.11 are vulnerable.
Vendor Status:
vBulletin as issued an update for this vulnerablity
