Multiple cross-site scripting (XSS) vulnerabilities in GuppY before 4.6.28 allow remote attackers to inject arbitrary web script or HTML via the (1) "an" parameter to agenda.php or (2) cat parameter to mobile/thread.php.
Directory traversal vulnerability in inc/includes.inc in GuppY 4.6.3 allows remote attackers to include and execute arbitrary local files via a .. (dot dot) in the selskin parameter to index.php. NOTE: this can be leveraged for remote file inclusion by including inc/boxleft.inc and specifying a URL in the xposbox[L][] array parameter.
Directory traversal vulnerability in error.php in GuppY 4.6.3, 4.5.16, and earlier allows remote attackers to include and execute arbitrary local files via a .. (dot dot) in the id parameter. NOTE: this can be leveraged to bypass authentication and upload arbitrary files by including admin/inc/upload.inc and specifying certain multipart/form-data input for admin/inc/upload.inc.