Heap-based buffer overflow in hfaxd in HylaFAX+ 5.2.4 through 5.5.3, when using LDAP authentication, might allow remote attackers to cause a denial of service (child hang) or execute arbitrary code via a long USER command.
http://www.securityfocus.com/bid/62729
http://www.securityfocus.com/archive/1/528943