The SMTP service in MERCUR Messaging 2005 before Service Pack 4 allows remote attackers to cause a denial of service (infinite loop) via a message in which neither the originator nor recipient address is known.
Multiple buffer overflows in MERCUR Messaging 2005 before Service Pack 4 allow remote attackers to cause a denial of service (crash) via (1) "long command lines at port 32000" and (2) certain name service queries that are not properly handled by the SMTP service.