There was an issue which was found in the Skype app for Android ( Version 3.2 ) and is said to have been already tested on smartphones such as Sony Xperia Z, , Huawei’s Premia 4G and even the Samsung Galaxy Note 2. I was unable to test it because I had some issues with the startup of the app , but even then I am providing an overview of the issue.
In order to exploit the vulnerability of the app , one would have to call the target handset from the second device via Skype which will cause the former to display a prompt on the screen to answer or reject the call. Adding more in detail , the call should be answered to on the target device using the green button and then ended on the initiating phone which will leave the former displaying the lock screen.
Such type of bugs have been detected on Viber and even VoIP for Android so there is no need to worry.