Multiple cross-site scripting (XSS) vulnerabilities in XOOPS 2.5.1.a, and possibly earlier versions, allow remote attackers to inject arbitrary web script or HTML via the (1) text parameter to include/formdhtmltextarea_preview.php or (2) img BBCODE tag within the message parameter to pmlite.php (aka Private Message). NOTE: some of these details are obtained from third party information.

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.

Multiple unspecified vulnerabilities in XOOPS before 2.4.0 Final have unknown impact and attack vectors.

mainfile.php in XOOPS 2.0.13.2 and earlier, when register_globals is enabled, allows remote attackers to overwrite variables such as $xoopsOption['nocommon'] and conduct directory traversal attacks or include PHP files via (1) xoopsConfig[language] to misc.php or (2) xoopsConfig[theme_set] to index.php, as demonstrated by injecting PHP sequences into a log file.