Stack-based buffer overflow in the IMAP service in Mercur Messaging 5.0 SP3 and earlier allows remote attackers to cause a denial of service (application crash) and possibly execute arbitrary code via a long string to the (1) LOGIN or (2) SELECT command, a different set of attack vectors and possibly a different vulnerability than CVE-2003-1177.

Buffer overflow in the base64 decoder in MERCUR Mailserver 4.2 before SP3a allows remote attackers to cause a denial of service and possibly execute arbitrary code via a long (1) AUTH command to the POP3 server or (2) AUTHENTICATE command to the IMAP server.