The (1) rand and (2) mt_rand functions in PHP 5.2.6 do not produce cryptographically strong random numbers, which allows attackers to leverage exposures in products that rely on these functions for security-relevant functionality, as demonstrated by the password-reset functionality in Joomla! 1.5.x and WordPress before 2.6.2, a different vulnerability than CVE-2008-2107, CVE-2008-2108, and CVE-2008-4102.

More... (http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2008-4107)