AOL Instant Messenger (AIM) 4.7 and earlier allows remote attackers to cause a denial of service (application crash) via a large number of different fonts followed by an HTML HR tag.
https://exchange.xforce.ibmcloud.com/vulnerabilities/7757
https://euvd.enisa.europa.eu/vulnerability/EUVD-2001-1401
http://www.securityfocus.com/bid/3756
http://www.securityfocus.com/archive/1/247707
http://www.securityfocus.com/archive/1/218920