Anti-virus powerhouse Symantec has released patches for <A HREF="http://www.eweek.com/article2/0,1895,1953579,00.asp">three "moderately critical" security vulnerabilities</A> that could put users at risk of security bypass and information exposure attacks. In an alert posted online, the vendor urged users to upgrade to Symantec Scan Engine 5.1 to protect against the threat of improper authentication for Web-based user logins. Symantec claims there are no known publicly available exploits. However, security researchers warn that proof-of-concept exploit code showing how a remote attacker can change the administrator password has already been published, raising the likelihood of targeted attacks.