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 sub-form 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-17-022