Pidgin is an instant messaging program which can log in to multiple accounts on multiple instant messaging networks simultaneously. An input sanitization flaw was found in the way the AOL Open System for Communication in Realtime protocol plug-in in Pidgin, used by the AOL ICQ and AIM instant messaging systems, escaped certain UTF-8 characters. A remote attacker could use this flaw to crash Pidgin via a specially-crafted OSCAR message. An input sanitization flaw was found in the way the Pidgin SILC protocol plug-in escaped certain UTF-8 characters in channel messages. A remote attacker could use this flaw to crash Pidgin via a specially-crafted SILC message. Multiple NULL pointer dereference flaws were found in the Jingle extension of the Extensible Messaging and Presence Protocol protocol plug-in in Pidgin. A remote attacker could use these flaws to crash Pidgin via a specially-crafted Jingle multimedia message. Red Hat would like to thank the Pidgin project for reporting these issues. Upstream acknowledges Evgeny Boger as the original reporter of CVE-2011-4601; Diego Bauche Madero from IOActive as the original reporter of CVE-2011-4603; and Thijs Alkemade as the original reporter of CVE-2011-4602. All Pidgin users should upgrade to these updated packages, which contain backported patches to resolve these issues. Pidgin must be restarted for this update to take effect.