A vulnerability in the offline access mode of Cisco Duo Two-Factor Authentication for macOS and Duo Authentication for Windows Logon and RDP could allow an unauthenticated, physical attacker to replay valid user session credentials and gain unauthorized access to an affected macOS or Windows device. This vulnerability exists because session credentials do not properly expire. An attacker could exploit this vulnerability by replaying previously used multifactor authentication (MFA) codes to bypass MFA protection. A successful exploit could allow the attacker to gain unauthorized access to the affected device.

A vulnerability in the smart card login authentication of Cisco Duo for macOS could allow an unauthenticated attacker with physical access to bypass authentication. This vulnerability exists because the assigned user of a smart card is not properly matched with the authenticating user. An attacker could exploit this vulnerability by configuring a smart card login to bypass Duo authentication. A successful exploit could allow the attacker to use any personal identity verification (PIV) smart card for authentication, even if the smart card is not assigned to the authenticating user.