The Identity v3 API in OpenStack Dashboard (Horizon) before 2013.2 does not require the current password when changing passwords for user accounts, which makes it easier for remote attackers to change a user password by leveraging the authentication token for that user.
CWE-287 - Improper Authentication
Improper (or broken) authentication attacks are widespread, and have accounted for many of the worst data breaches in recent years. Improper authentication attacks are a class of vulnerabilities where an attacker impersonates a legitimate user by exploiting weaknesses in either session management or credential management to gain access to the user’s account. This can result in disclosure of sensitive information, and can lead to system compromise, theft, identity theft, and fraud.