An Unsupported Feature in the UI vulnerability in Juniper Networks Junos OS on MX Series and EX9200 Series allows an unauthenticated, network-based attacker to cause partial impact to the integrity of the device. If the "tcp-reset" option is added to the "reject" action in an IPv6 filter which matches on "payload-protocol", packets are permitted instead of rejected. This happens because the payload-protocol match criteria is not supported in the kernel filter causing it to accept all packets without taking any other action.

As a fix the payload-protocol match will be treated the same as a "next-header" match to avoid this filter bypass. This issue doesn't affect IPv4 firewall filters. This issue affects Juniper Networks Junos OS on MX Series and EX9200 Series: All versions earlier than 20.4R3-S7; 21.1 versions earlier than 21.1R3-S5; 21.2 versions earlier than 21.2R3-S5; 21.3 versions earlier than 21.3R3-S4; 21.4 versions earlier than 21.4R3-S4; 22.1 versions earlier than 22.1R3-S2; 22.2 versions earlier than 22.2R3-S2; 22.3 versions earlier than 22.3R2-S2, 22.3R3; * 22.4 versions earlier than 22.4R1-S2, 22.4R2-S2, 22.4R3.