Auth bypass in Juniper Networks Session Smart Router
CVE-2026-103409
A Missing authentication for critical function vulnerability in Juniper Networks Session Smart Router allows an unauthenticated network-based attacker to obtain administrative privileges by passing crafted URL parameters to an insecure endpoint running as root. Note that this vulnerability can only be exploited prior to the device being onboarded to Mist/Conductor. The issue can no longer be exploited once a device is onboarded to Mist/Conductor.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- supportportal.juniper.net/JSA112183 (vendor-advisory)
Frequently asked questions
- What is CVE-2026-103409?
- CVE-2026-103409 is a critical-severity vulnerability in Juniper Networks Session Smart Router, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2026-10-28.
- How severe is CVE-2026-103409?
- Critical severity. CVSS v3 base score is 9.8 out of 10.