proxy.c in libpurple in Pidgin before 2.10.4 does not properly handle canceled SOCKS5 connection attempts, which allows user-assisted remote authenticated users to cause a denial of service (application crash) via a sequence of XMPP file-transfer requests.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A17886
http://www.mandriva.com/security/advisories?name=MDVSA-2012:082