Researchers have discovered a serious weakness in virtually all websites protected by the secure sockets layer protocol that allows attackers to silently decrypt data that's passing between a webserver and an end-user browser.
The vulnerability resides in versions 1.0 and earlier of TLS, or transport layer security, the successor to the secure sockets layer technology that serves as the internet's foundation of trust. Although versions 1.1 and 1.2 of TLS aren't susceptible, they remain almost entirely unsupported in browsers and websites alike, making encrypted transactions on PayPal, GMail, and just about every other website vulnerable to eavesdropping by hackers who are able to control the connection between the end user and the website he's visiting.
Source : www.theregister.co.uk