An issue was discovered in Foxit Reader before 9.1 and PhantomPDF before 9.1. This vulnerability allows remote attackers to execute arbitrary code. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the u3d images inside of a pdf. The issue results from the lack of proper validation of user-supplied data, which can result in an array indexing issue. An attacker can leverage this to execute code in the context of the current process.
https://www.foxitsoftware.com/support/security-bulletins.php