Padding bytes in Ethernet packets on PA-200, PA-220, PA-500, PA-800, PA-2000 Series, PA-3000 Series, PA-3200 Series, PA-5200 Series, and PA-7000 Series firewalls are not cleared before the data frame is created. This leaks a small amount of random information from the firewall memory into the Ethernet packets. An attacker on the same Ethernet subnet as the PAN-OS firewall is able to collect potentially sensitive information from these packets.

This issue is also known as Etherleak and is detected by security scanners as CVE-2003-0001.
This issue impacts:
PAN-OS 8.1 version earlier than PAN-OS 8.1.18;
PAN-OS 9.0 versions earlier than PAN-OS 9.0.12;
PAN-OS 9.1 versions earlier than PAN-OS 9.1.5.
Source: NIST