Adobe Reader and Acrobat 9.x before 9.4, and 8.x before 8.2.5 on Windows and Mac OS X, allow attackers to execute arbitrary code via unspecified vectors, related to a "prefix protocol handler vulnerability."
Gentoo Linux Security Advisory 201101-8 - Multiple vulnerabilities in Adobe Reader might result in the execution of arbitrary code. Versions less than 9.4.1 are affected.