Adobe Flash Player versions 25.0.0.148 and earlier have an exploitable use after free vulnerability when handling multiple mask properties of display objects, aka memory corruption. Successful exploitation could lead to arbitrary code execution.
https://security.gentoo.org/glsa/201705-12
https://helpx.adobe.com/security/products/flash-player/apsb17-15.html
https://access.redhat.com/errata/RHSA-2017:1219