An improper authentication vulnerability exists in Palo Alto Networks PAN-OS software that enables a SAML authenticated attacker to impersonate any other user in the GlobalProtect Portal and GlobalProtect Gateway when they are configured to use SAML authentication. This issue impacts: PAN-OS 8.1 versions earlier than PAN-OS 8.1.19; PAN-OS 9.0 versions earlier than PAN-OS 9.0.14; PAN-OS 9.1 versions earlier than PAN-OS 9.1.9; PAN-OS 10.0 versions earlier than PAN-OS 10.0.5. PAN-OS 10.1 versions are not impacted.