Nasdaq's website may be a ticking a time bomb for a major security breach, including a takeover by hackers, a cybersecurity expert warns.

Ilia Kolochenko, chief executive of Swiss information security company High-Tech Bridge, said he warned the exchange three weeks ago that Nasdaq.com had holes in its security. He said the weaknesses made it possible for hackers to steal users' browser histories and cookies or perform phishing attacks that could result in the theft of confidential data, according to the New York Daily News.