A security restriction bypass vulnerability has been discovered in Revive Adserver version < 5.0.5 by HackerOne user hoangn144. Revive Adserver, like many other applications, requires the logged in user to type the current password in order to change the e-mail address or the password. It was however possible for anyone with access to a Revive Adserver admin user interface to bypass such check and change e-email address or password of the currently logged in user by altering the form payload.The attack requires physical access to the user interface of a logged in user. If the POST payload was altered by turning the “pwold” parameter into an array, Revive Adserver would fetch and authorise the operation even if no password was provided.