CVE-2021-31349: Juniper 128 Technology Session Smart Router Firmware

Critical severity, CVSS 9.8. EPSS: 1.7% chance of exploitation in the next 30 days.

The usage of an internal HTTP header created an authentication bypass vulnerability (CWE-287), allowing an attacker to view internal files, change settings, manipulate services and execute arbitrary code. This issue affects all Juniper Networks 128 Technology Session Smart Router versions prior to 4.5.11, and all versions of 5.0 up to and including 5.0.1.

Affected products

• Juniper 128 Technology Session Smart Router Firmware: before 4.5.11 (fixed in 4.5.11); from 5.0.0, up to and including 5.0.1

Published 2021-10-19. Last modified 2026-06-17.