CVE-2025-21589: Juniper Networks Session Smart Conductor

Critical severity, CVSS 9.8. EPSS: 1.6% chance of exploitation in the next 30 days.

An Authentication Bypass Using an Alternate Path or Channel vulnerability in Juniper Networks Session Smart Router may allows a network-based attacker to bypass authentication and take administrative control of the device. This issue affects Session Smart Router:  * from 5.6.7 before 5.6.17,  * from 6.0 before 6.0.8 (affected from 6.0.8), * from 6.1 before 6.1.12-lts,  * from 6.2 before 6.2.8-lts,  * from 6.3 before 6.3.3-r2;  This issue affects Session Smart Conductor:  * from 5.6.7 before 5.6.17,  * from 6.0 before 6.0.8 (affected from 6.0.8), * from 6.1 before 6.1.12-lts,  * from 6.2 before 6.2.8-lts,  * from 6.3 before 6.3.3-r2;  This issue affects WAN Assurance Managed Routers:  * from 5.6.7 before 5.6.17,  * from 6.0 before 6.0.8 (affected from 6.0.8), * from 6.1 before 6.1.12-lts,  * from 6.2 before 6.2.8-lts,  * from 6.3 before 6.3.3-r2.

Affected products

• Juniper Networks Session Smart Conductor: from 5.6.7, before 5.6.17 (fixed in 5.6.17); from 6.1, before 6.1.12-lts (fixed in 6.1.12-lts); from 6.2, before 6.2.8-lts (fixed in 6.2.8-lts); from 6.3, before 6.3.3-r2 (fixed in 6.3.3-r2)
• Juniper Networks Session Smart Router: from 5.6.7, before 5.6.17 (fixed in 5.6.17); from 6.1, before 6.1.12-lts (fixed in 6.1.12-lts); from 6.2, before 6.2.8-lts (fixed in 6.2.8-lts); from 6.3, before 6.3.3-r2 (fixed in 6.3.3-r2)
• Juniper Networks WAN Assurance Managed Router: from 5.6.7, before 5.6.17 (fixed in 5.6.17); from 6.1, before 6.1.12-lts (fixed in 6.1.12-lts); from 6.2, before 6.2.8-lts (fixed in 6.2.8-lts); from 6.3, before 6.3.3-r2 (fixed in 6.3.3-r2)

Published 2026-01-27. Last modified 2026-06-17.