Adobe Flash Player versions 26.0.0.137 and earlier have an exploitable type confusion vulnerability when parsing SWF files. Successful exploitation could lead to arbitrary code execution.
https://www.exploit-db.com/exploits/42480/
https://security.gentoo.org/glsa/201709-16
https://helpx.adobe.com/security/products/flash-player/apsb17-23.html
https://access.redhat.com/errata/RHSA-2017:2457