Adobe Flash Player versions 23.0.0.207 and earlier, 11.2.202.644 and earlier have security bypass vulnerability in the implementation of the same origin policy.
https://security.gentoo.org/glsa/201701-17
https://helpx.adobe.com/security/products/flash-player/apsb16-39.html
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2016/ms16-154