The XMPP protocol plugin in libpurple in Pidgin before 2.10.1 does not properly handle missing fields in (1) voice-chat and (2) video-chat stanzas, which allows remote attackers to cause a denial of service (application crash) via a crafted message.
developer.pidgin.im/viewmtn/revision/info/fb216fc88b085afc06d9a15209519cde1f4df6c6
pidgin.im/news/security/?id=58
secunia.com/advisories/47219
secunia.com/advisories/47234
www.redhat.com/support/errata/RHSA-2011-1820.html
www.redhat.com/support/errata/RHSA-2011-1821.html
hermes.opensuse.org/messages/13195955
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A18420