CVE-2000-1006
Microsoft Exchange Server 5.5 does not properly handle a MIME header with a blank charset specified, which allows remote attackers to cause a denial of service via a charset="" command, aka the "Malformed MIME Header" vulnerability.
Date published : 2001-01-22
http://www.securityfocus.com/bid/1869
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2000/ms00-082