Stack-based buffer overflow in the MailCheck821Address function in nnotes.dll in the nrouter.exe service in the server in IBM Lotus Domino 8.0.x before 8.0.2 FP5 and 8.5.x before 8.5.1 FP2 allows remote attackers to execute arbitrary code via a long e-mail address in an ORGANIZER:mailto header in an iCalendar calendar-invitation e-mail message, aka SPR NRBY7ZPJ9V.