The "internal state tracking" code for the random and urandom devices in FreeBSD 5.5, 6.1 through 6.3, and 7.0 beta 4 allows local users to obtain portions of previously-accessed random values, which could be leveraged to bypass protection mechanisms that rely on secrecy of those values.

More... (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2007-6150)