Vulnerability Instance

Security researcher Amit Klein reported that it
was possible to reverse engineer the value used to
seed Math.random().  Since the pseudo-random number
generator was only seeded once per browsing session, this seed value
could be used as a unique token to identify and track users across
different web sites.Update (October 27, 2010): After the Firefox 3.6.4
and Firefox 3.5.10 releases, Amit Klein reported that there was an
additional unfixed case where user tracking could occur using the
above-mentioned technique and a pop-up window or iframe that was
subsequently navigated by the user.  This additional variant is
identified as CVE-2010-3171.