Authd, through version 0.3.6, did not sufficiently randomize user IDs to prevent collisions. A local attacker who can register user names could spoof another user's ID and gain their privileges.

Authd PAM module before version 0.3.5 can allow broker-managed users to impersonate any other user managed by the same broker and perform any PAM operation with it, including authenticating as them.

authd sets weak permissions for /etc/ident.key, which allows local users to obtain the key by leveraging a race condition between the creation of the key, and the chmod to protect it.