I found this earlier today and was wondering if it was fixed in 6.5.2?
IBM Lotus Domino Web Access message handling denial of service
Vulnerability aggregator Secunia is warning of a moderate vulnerability in IBM Lotus Domino Web Access (formerly called iNotes) 6.x that could be exploited by an attacker to cause a remote denial of service. Secunia reported that the vulnerability is caused due to an unspecified error when processing mail and can be exploited by sending mail containing an overly large, specially crafted ,jpg image attachment (about 12 MB) to a vulnerable system. Successful exploitation reportedly crashes the Domino server when the mail is opened. Domino 6.5.1 is vulnerable; the flaw may affect other versions as well. A fix will reportedly not be issued, but Secunia recommended limiting the maximum message size as a workaround.
Here is a link