CVE-2026-103401: Juniper Session Smart Router link following arbitrary file overwrite

CVE-2026-103401 · Severity: high · CVSS 8.8 · Published 2026-10-28

Juniper's Session Smart Router and Conductor are network routing devices that direct traffic for enterprises. A flaw in their web API allows a local attacker to overwrite system files as root without authentication, potentially enabling system compromise or denial of service. Only Mist-managed routers and unmanaged routers are vulnerable; those connected to a Conductor are protected.

Technologies: Juniper Networks Session Smart Conductor, Juniper Networks Session Smart Router. Vendors: Juniper Networks.

Quick answers

Is CVE-2026-103401 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-103401 being exploited in the wild.
How severe is CVE-2026-103401?
High severity, with a CVSS score of 8.8, published 28 October 2026.
Which products and versions are affected?
Juniper Networks Session Smart Router; Juniper Networks Session Smart Conductor.
Is there a fix for CVE-2026-103401?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-103401 attacked?
It is attacked with local access, in a network appliance.
Am I affected by CVE-2026-103401?
Check whether you run Juniper Networks Session Smart Conductor or Juniper Networks Session Smart Router. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An improper link resolution (symlink following) vulnerability exists in unauthenticated web server API handlers. A local unprivileged user can exploit this to write arbitrary files with root privileges via symlink traversal. Exploitation is limited to Mist-managed routers and routers not yet onboarded to a Conductor; machines under Conductor management are not affected.

Affected products

  • Juniper Networks Session Smart Router
  • Juniper Networks Session Smart Conductor

Timeline

  • 2026-10-28: disclosed

References

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