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 126.96.36.199
System Compromise: remote attackers can gain control of vulnerable systems.
Update to version 188.8.131.52 or later.