CVE 2010-4568
Bugzilla 2.14 through 2.22.7; 3.0.x, 3.1.x, and 3.2.x before 3.2.10; 3.4.x before 3.4.10; 3.6.x before 3.6.4; and 4.0.x before 4.0rc2 does not properly generate random values for cookies and tokens, which allows remote attackers to obtain access to arbitrary accounts via unspecified vectors, related to an insufficient number of calls to the srand function.
See the 
CVE page on Mitre.org
for more details.
