The Exchange Collaboration Data Objects (EXCDO) functionality in Microsoft Exchange Server 2000 SP3, 2003 SP1 and SP2, and 2007 allows remote attackers to cause a denial of service (crash) via an Internet Calendar (iCal) file containing multiple X-MICROSOFT-CDO-MODPROPS (MODPROPS) properties in which the second MODPROPS is longer than the first, which triggers a NULL pointer dereference and an unhandled exception.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A1593
https://exchange.xforce.ibmcloud.com/vulnerabilities/33888
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2007/ms07-026
http://www.vupen.com/english/advisories/2007/1711
http://www.us-cert.gov/cas/techalerts/TA07-128A.html
http://www.securitytracker.com/id?1018015
http://www.securityfocus.com/bid/23808
http://www.securityfocus.com/archive/1/468871/100/200/threaded
http://www.securityfocus.com/archive/1/468047/100/0/threaded
http://secunia.com/advisories/25183
http://lists.grok.org.uk/pipermail/full-disclosure/2007-May/063232.html