A problem with the implementation of the MACsec protocol in Palo Alto Networks PAN-OS® results in the cleartext exposure of the connectivity association key (CAK). This issue is only applicable to PA-7500 Series devices which are in an NGFW cluster. A user who possesses this key can read messages being sent between devices in a NGFW Cluster. There is no impact in non-clustered firewalls or clusters of firewalls that do not enable MACsec.