CVE-2024-21597: Juniper Junos

High severity, CVSS 7.5. EPSS: 0.4% chance of exploitation in the next 30 days.

An Exposure of Resource to Wrong Sphere vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX Series allows an unauthenticated, network-based attacker to bypass the intended access restrictions. In an Abstracted Fabric (AF) scenario if routing-instances (RI) are configured, specific valid traffic destined to the device can bypass the configured lo0 firewall filters as it's received in the wrong RI context. This issue affects Juniper Networks Junos OS on MX Series: * All versions earlier than 20.4R3-S9; * 21.2 versions earlier than 21.2R3-S3; * 21.4 versions earlier than 21.4R3-S5; * 22.1 versions earlier than 22.1R3; * 22.2 versions earlier than 22.2R3; * 22.3 versions earlier than 22.3R2.

Affected products

• Juniper Junos: version 20.4 only; version 21.2 only; version 21.4 only; version 22.1 only; version 22.2 only; version 22.3 only

Published 2024-01-12. Last modified 2026-06-17.