Pidgin is an instant messaging program which can log in to multiple accounts on multiple instant messaging networks simultaneously. A buffer overflow flaw was found in the way Pidgin initiates file transfers when using the Extensible Messaging and Presence Protocol . If a Pidgin client initiates a file transfer, and the remote target sends a malformed response, it could cause Pidgin to crash or, potentially, execute arbitrary code with the permissions of the user running Pidgin. This flaw only affects accounts using XMPP, such as Jabber and Google Talk. A denial of service flaw was found in Pidgin"s QQ protocol decryption handler. When the QQ protocol decrypts packet information, heap data can be overwritten, possibly causing Pidgin to crash. A flaw was found in the way Pidgin"s PurpleCircBuffer object is expanded. If the buffer is full when more data arrives, the data stored in this buffer becomes corrupted. This corrupted data could result in confusing or misleading data being presented to the user, or possibly crash Pidgin. It was discovered that on 32-bit platforms, the Red Hat Security Advisory RHSA-2008:0584 provided an incomplete fix for the integer overflow flaw affecting Pidgin"s MSN protocol handler. If a Pidgin client receives a specially-crafted MSN message, it may be possible to execute arbitrary code with the permissions of the user running Pidgin. Note: By default, when using an MSN account, only users on your buddy list can send you messages. This prevents arbitrary MSN users from exploiting this flaw. 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.