Seems like this year has been really hard on Office Web Apps and Word Services within SharePoint 2010 / 2013 for security reasons.
Microsoft released another security bulletin that impacts:
Here is the security bulletin that is ranked as critical.
Microsoft Security Bulletin MS14-081 – Critical
Vulnerabilities in Microsoft Word and Microsoft Office Web Apps Could Allow Remote Code Execution (3017301)
Following are the important resources on this issue.
No workaround available so far.