This indicates an attempt to exploit a boundry error in Skype.
Skype is vulnerable to a boundary error in Skype4COM.dll, in the "skype4com" URI handler. The error occurs when processing short strings through a web browser. As a result an attacker can execute arbitrary code on a vulnerable system.
Skype versions older than 184.108.40.206
System Compromise: remote attackers can gain control of vulnerable systems.
Update to version 220.127.116.11 or later.