From $URL: Yesterday a vulnerability was discovered: a specially crafted URL could be requested that would allow an attacker to bypass a security check to verify a user requested a password reset. As a result, the first account without a key in the database (usually the admin account) would have its password reset and a new password would be emailed to the account owner. This doesn’t allow remote access, but it is very annoying.
2.8.4 in CVS.
CVE-2009-2762 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2009-2762): wp-login.php in WordPress 2.8.3 and earlier allows remote attackers to force a password reset for the first user in the database, possibly the administrator, via a key[] array variable in a resetpass (aka rp) action, which bypasses a check that assumes that $key is not an array.