Shares of professional social networking company LinkedIn Corp could fall by half if the company hits a rough patch, Barron's said in its May 23 issue.

LinkedIn, whose shares more than doubled after the company went public last week, will find it hard to justify its high valuation and investors "should stay away," according to CIOL.

LinkedIn shares are trading at 35 times its 2010 revenue and 550 times 2010 profit, levels Barron's called "steep."

Meanwhile, according to a security researcher, LinkedIn's professional networking website has security flaws that makes users' accounts vulnerable to attack by hackers who could break in without ever needing passwords.

New Delhi-based Internet security researcher Rishi Narang who discovered the security flaw told Reuters that the problem is related to the way LinkedIn manages a commonly used type of data file known as a cookie.