CVE-2024-39519: Junos OS Evolved: ACX 7000 Series: Multicast traffic is looped in a multihoming EVPN MPLS scenario

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-07-11 · updated 2026-06-17
Weakness: CWE-754

Description

An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS Evolved on ACX7000 Series allows an unauthenticated, adjacent attacker to cause a Denial-of-Service (DoS). On all ACX 7000 Series platforms running Junos OS Evolved, and configured with IRBs, if a Customer Edge device (CE) device is dual homed to two Provider Edge devices (PE) a traffic loop will occur when the CE sends multicast packets. This issue can be triggered by IPv4 and IPv6 traffic. This issue affects Junos OS Evolved: All versions from 22.2R1-EVO and later versions before 22.4R2-EVO, This issue does not affect Junos OS Evolved versions before 22.1R1-EVO.

Affected products

Juniper Networks Junos OS Evolved: from 22.2 before 22.4; 22.4, 22.4-r1, 22.4-r1-s1, 22.4-r1-s2 — fixed in 22.4

How to fix

Upgrade to a fixed version: Juniper Networks Junos OS Evolved 22.4. Check the vendor advisory for mitigations.

References

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