# CVE-2024-21607

## Summary

- **CVE ID:** CVE-2024-21607
- **Severity:** MEDIUM
- **CVSS Score:** 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N)
- **CWE:** CWE-447
- **Published:** Jan 12, 2024
- **Last Modified:** Mar 13, 2026

## Description

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.

## Affected Products

- Juniper Networks — Junos OS (0)
- Juniper Networks — Junos OS (21.1)
- Juniper Networks — Junos OS (21.2)
- Juniper Networks — Junos OS (21.3)
- Juniper Networks — Junos OS (21.4)
- Juniper Networks — Junos OS (22.1)
- Juniper Networks — Junos OS (22.2)
- Juniper Networks — Junos OS (22.3)
- Juniper Networks — Junos OS (22.4)

## References

- [CNA](https://supportportal.juniper.net/JSA75748)
- [CNA](https://www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.31%
- **EPSS Percentile:** 23.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._