The activation resend function in the Profiles module in XOOPS before 2.4.1 sends activation codes in response to arbitrary activation requests, which allows remote attackers to bypass administrative approval via a request involving activate.php.
The custom avatar uploading feature (uploader.php) for XOOPS 2.0.9.2 and earlier allows remote attackers to upload arbitrary PHP scripts, whose file extensions are not filtered.
Cross-site scripting (XSS) vulnerability in the MytextSanitizer function in XOOPS 1.3.5 through 1.3.9 and XOOPS 2.0 through 2.0.1 allows remote attackers to inject arbitrary web script or HTML via a javascript: URL in an IMG tag.