Shorewall Firewall versions 2.2.x and 2.4.x allow any client to bypass any rule as long as they are accepted by the MAC filter.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/38756/shorewallMAC.txt
Source: https://packetstormsecurity.com/files/38756/shorewallMAC.txt.html