bitlbee-libpurple before 3.5.1 allows remote attackers to cause a denial of service (NULL pointer dereference and crash) and possibly execute arbitrary code via a file transfer request for a contact that is not in the contact list. NOTE: this vulnerability exists because of an incomplete fix for CVE-2016-10189.
https://github.com/bitlbee/bitlbee/commit/30d598ce7cd3f136ee9d7097f39fa9818a272441
https://bugs.bitlbee.org/ticket/1282
http://www.securityfocus.com/bid/95932