This page has extensive information on CVE-2014-0160, an information disclosure vulnerability in OpenSSL otherwise known as the "heartbleed bug." "The Heartbleed bug allows anyone on the Internet to read the memory of the systems protected by the vulnerable versions of the OpenSSL software. This compromises the secret keys used to identify the service providers and to encrypt the traffic, the names and passwords of the users and the actual content. This allows attackers to eavesdrop communications, steal data directly from the services and users and to impersonate services and users." See also this OpenSSL advisory; version 1.0.1g contains the fix.
April 7, 2014
The OpenSSL "Heartbleed" Vulnerability
Read more at LWN