The Store Service in Microsoft Exchange 2000 allows remote attackers to cause a denial of service (CPU consumption) via a mail message with a malformed RFC message attribute, aka "Malformed Mail Attribute can Cause Exchange 2000 to Exhaust CPU Resources."
https://euvd.enisa.europa.eu/vulnerability/EUVD-2002-0365
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2002/ms02-025