The flaw affects the "People app", which is the default app for keeping contact information on Android devices.
The People app calendar goes from November 2012 straight to January 2013.
Android is Google's operating system. Version 4.2 was launched in October 2012.
Other Google calendars are unaffected by the flaw."
More about it on the BBC site: http://www.bbc.co.uk/news/technology-20392386