HexView has discovered a vulnerability in Microsoft Word, which can be exploited by malicious people to cause a DoS (Denial of Service) and potentially compromise a user's system. The vulnerability is caused due to an input validation error within the parsing of document files and may lead to a stack-based buffer overflow.
This can be exploited to crash the process when the user opens a specially crafted document. However, due to the nature of the problem, execution of arbitrary code may potentially also be possible, though it has not been proven.
Open trusted documents only. For Internet Explorer users, documents on web sites can be opened automatically in the browser, unless the security level for the "Internet" security zone is set to "High" or the "File download" setting has been disabled.
News source: Secunia