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 Xoops 1.0 RC3 allows remote attackers to inject arbitrary web script or HTML via Javascript in an IMG tag when submitting news.
Cross-site scripting (XSS) vulnerability in the Quizz module for XOOPS 1.0, when allowing on-line question development, allows remote attackers to inject arbitrary web script or HTML via a javascript: URL in the SRC attribute of an IMG tag.