CVE-2023-44190: Junos OS Evolved: PTX10001, PTX10004, PTX10008, PTX10016: MAC address validation bypass vulnerability

Severity: medium (CVSS 5.4 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: 2023-10-11 · updated 2026-06-17
Weakness: CWE-346

Description

An Origin Validation vulnerability in MAC address validation of Juniper Networks Junos OS Evolved on PTX10001, PTX10004, PTX10008, and PTX10016 devices allows a network-adjacent attacker to bypass MAC address checking, allowing MAC addresses not intended to reach the adjacent LAN to be forwarded to the downstream network. Due to this issue, the router will start forwarding traffic if a valid route is present in forwarding-table, causing a loop and congestion in the downstream layer-2 domain connected to the device. This issue affects Juniper Networks Junos OS Evolved on PTX10001, PTX10004, PTX10008, and PTX10016: * All versions prior to 21.4R3-S5-EVO; * 22.1 versions prior to 22.1R3-S4-EVO; * 22.2 versions 22.2R1-EVO and later; * 22.3 versions prior to 22.3R2-S2-EVO, 22.3R3-S1-EVO; * 22.4 versions prior to 22.4R2-S1-EVO, 22.4R3-EVO; * 23.2 versions prior to 23.2R1-S1-EVO, 23.2R2-EVO.

Affected products

Juniper Networks Junos OS Evolved: before 21.4; 21.4, 21.4-r1, 21.4-r1-s1, 21.4-r1-s2, 21.4-r2, 21.4-r2-s1 (+32) — fixed in 21.4

How to fix

Upgrade to a fixed version: Juniper Networks Junos OS Evolved 21.4. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2023-44190 or the next vulnerability affects your stack