Adobe Acrobat Reader versions 15.020.20042 and earlier, 15.006.30244 and earlier, 11.0.18 and earlier have an exploitable use after free vulnerability in the XFA engine, related to validation functionality. Successful exploitation could lead to arbitrary code execution.
https://helpx.adobe.com/security/products/acrobat/apsb17-01.html
http://www.zerodayinitiative.com/advisories/ZDI-17-025