Juniper Junos OS: 2024-01 Security Bulletin: Junos OS: MX Series and EX9200 Series: If the "tcp-reset" option used in an IPv6 filter, matched packets are accepted instead of rejected (JSA75748) (CVE-2024-21607)

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.