Vvveb is a powerful and easy to use CMS with page builder to build websites, blogs or ecommerce stores. Prior to 1.0.8.5, app/controller/user/profile.php accepts the user[bio] field and passes stored content through sanitizeHTML() in system/functions.php, whose on* event-handler regular expression omits the forward-slash delimiter and whose do-while condition compares the string to itself, so forbidden nested tags are removed only once. An Author-role or higher user can submit solidus-prefixed event-handler markup or nested forbidden tags that survive sanitization. The stored bio is rendered without sufficient output encoding on /author/{username}, in the admin user-management view, and potentially in comment displays, causing attacker-controlled JavaScript to execute when unauthenticated visitors, administrators, or other users view the content. This can expose browser-session data and permit victim-context account actions, defacement, or phishing. This issue is fixed in version 1.0.8.5.