Gadu-Gadu 7.20 allows remote attackers to cause a denial of service (crash and configuration loss) via a page with a large number of gg: URIs.
https://exchange.xforce.ibmcloud.com/vulnerabilities/23153
http://www.securityfocus.com/bid/15520/
http://secunia.com/advisories/17597/
http://marc.info/?l=bugtraq&m=113261573023912&w=2
http://archives.neohapsis.com/archives/fulldisclosure/2005-11/0658.html