Microsoft Exchange Server 2007 SP3 and 2010 SP1 and SP2 allows remote authenticated users to cause a denial of service (Information Store service hang) by subscribing to a crafted RSS feed, aka "RSS Feed May Cause Exchange DoS Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A16158
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2012/ms12-080