The STUN protocol implementation in libpurple in Pidgin before 2.10.8 allows remote STUN servers to cause a denial of service (out-of-bounds write operation and application crash) by triggering a socket read error.
https://rhn.redhat.com/errata/RHSA-2014-0139.html
http://www.ubuntu.com/usn/USN-2100-1
http://www.debian.org/security/2014/dsa-2859
http://pidgin.im/news/security/?id=79
http://lists.opensuse.org/opensuse-updates/2014-03/msg00005.html
http://lists.opensuse.org/opensuse-updates/2014-02/msg00039.html