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.
https://www.htbridge.com/advisory/HTB23176
https://exchange.xforce.ibmcloud.com/vulnerabilities/88247
http://www.freeguppy.org/thread.php?lng=en&pg=244900&cat=200
http://packetstormsecurity.com/files/123747
http://archives.neohapsis.com/archives/bugtraq/2013-10/0111.html