The local_handler_callback function in server/responder/pam/pam_LOCAL_domain.c in sssd 0.4.1 does not properly handle blank-password accounts in the SSSD BE database, which allows context-dependent attackers to obtain access by sending the account's username, in conjunction with an arbitrary password, over an ssh connection.

sssd: DoS in sssd PAM responder can prevent logins

The pam_parse_in_data_v2 function in src/responder/pam/pamsrv_cmd.c in the PAM responder in SSSD 1.5.0, 1.4.x, and 1.3 allows local users to cause a denial of service (infinite loop, crash, and login prevention) via a crafted packet.