A new post appeared on the WordPress discussion list today revealing more details about the process. Everyone is apparently able to reset a WordPress password if the email address of the WordPress user is known. All that needs to be done is to point the web browser at http://www.domain.com/wp-login.php?action=lostpassword to reset the password. The email address of the account holder has to be supplied in the form. WordPress usually will send a confirmation email first asking the email account owner if the password should be reset. The vulnerability manipulates the query to skip this step.

It is not possible to exploit this vulnerability further which means attackers cannot get access to the user account. It can however be theoretically be used to reset the password regularly to lock the user or admin out of the WordPress blog.

A temporary fix for the remote admin password reset vulnerability was posted. WordPress administrators need to change one line of code in the wp-login.php file of the WordPress installation to protect their blog from the attack. There is no official release fixing this problem, apply this changeset to your wp-login.php.

change line 190 in wp-login.php to

if ( empty( $key ) )

With

    if ( empty( $key ) || is_array( $key ) )

It is advised to apply the temporary fix as soon as possible to WordPress installations.