Macromedia Flash Plugin before 6,0,47,0 allows remote attackers to bypass the same-domain restriction and read arbitrary files via (1) an HTTP redirect, (2) a "file://" base in a web document, or (3) a relative URL from a web archive (mht file).
https://euvd.enisa.europa.eu/vulnerability/EUVD-2002-1450
http://www.securityfocus.com/bid/5429
http://www.macromedia.com/v1/handlers/index.cfm?ID=23294