Junos OS: MX Series and EX9200 Series: If the "tcp-reset" option used in an IPv6 filter, matched packets are accepted instead of rejected

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.