upnp.c in libpurple in Pidgin before 2.10.7 does not properly terminate long strings in UPnP responses, which allows remote attackers to cause a denial of service (application crash) by leveraging access to the local network.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A18221
http://www.ubuntu.com/usn/USN-1746-1
http://www.pidgin.im/news/security/?id=68
http://lists.opensuse.org/opensuse-security-announce/2013-03/msg00007.html
http://lists.opensuse.org/opensuse-security-announce/2013-03/msg00006.html
http://lists.opensuse.org/opensuse-security-announce/2013-03/msg00003.html