Adobe Reader and Acrobat 9.x before 9.2, 8.x before 8.1.7, and possibly 7.x through 7.1.4 do not properly perform XMP-XML entity expansion, which allows remote attackers to cause a denial of service via a crafted document.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6280
http://www.vupen.com/english/advisories/2009/2898
http://www.us-cert.gov/cas/techalerts/TA09-286B.html
http://www.securityfocus.com/bid/36638
http://www.adobe.com/support/security/bulletins/apsb09-15.html