Uptime Kuma is an easy-to-use self-hosted monitoring tool. Prior to version 1.23.9, when a user changes their login password in Uptime Kuma, a previously logged-in user retains access without being logged out. This behavior persists consistently, even after system restarts or browser restarts. This vulnerability allows unauthorized access to user accounts, compromising the security of sensitive information. The same vulnerability was partially fixed in CVE-2023-44400, but logging existing users out of their accounts was forgotten. To mitigate the risks associated with this vulnerability, the maintainers made the server emit a `refresh` event (clients handle this by reloading) and then disconnecting all clients except the one initiating the password change. It is recommended to update Uptime Kuma to version 1.23.9.
Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.