A remote code execution vulnerability exists when Skype for Business and Microsoft Lync clients fail to properly sanitize specially crafted content, aka "Remote Code Execution Vulnerability in Skype For Business and Lync." This affects Skype, Microsoft Lync.
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8311
http://www.securitytracker.com/id/1041260