Juniper Session Smart Router/Conductor: Arbitrary file overwrite as root via link following
Summary
Juniper Session Smart Router (SSR) and Session Smart Conductor contain a link following flaw (CWE-59) in unauthenticated web server handlers. Through unauthenticated API endpoints, an attacker can overwrite arbitrary files as root, which can lead to full compromise of the device. The issue affects Mist-managed routers and unmanaged routers not yet onboarded to a Conductor; routers already managed by a Conductor are described as not affected. The CVSS vector assumes network access with low privileges, while the description refers to a local unprivileged user, so the conflicting wording should be clarified with the vendor.
Affected
- Session Smart Router: before 7.0.5; 7.1.0 to before 7.1.7; 7.2.0 to before 7.2.3
- Session Smart Conductor: before 7.0.5; 7.1.0 to before 7.1.7; 7.2.0 to before 7.2.3
- Scope: Mist-managed routers and unmanaged routers not yet onboarded to a Conductor. Routers already managed by a Conductor are described as not affected.
- Version ranges to be confirmed in JSA112183.
Fixed in
- 7.0.5 and later
- 7.1.7 and later
- 7.2.3 and later
Workaround
- Juniper states there are no known workarounds.
- Interim measure (not a vendor workaround): restrict access to Conductor and router management interfaces until patched.
Exploitation
- Juniper SIRT is not aware of any malicious exploitation.
- No public proof of concept found for this CVE.
- NVD analysis was pending at the time of writing.
Our recommendation
- Inventory all SSR routers and Conductors, and identify Mist-managed or not yet onboarded units.
- Confirm affected and fixed versions in JSA112183.
- Upgrade to 7.0.5, 7.1.7, 7.2.3 or later. Patch the whole release train, as the same bulletin covers further Session Smart issues.
- Restrict management and web interface access until patching is complete, and check whether these interfaces are reachable from the internet.
- Monitor the advisory and NVD for updates.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Juniper Security Advisory JSA112183 supportportal.juniper.net
- Strix CVE record CVE-2026-103401 www.strix.ai
- Mallory analysis mallory.ai
- SecurityOnline: Juniper Session Smart Router vulnerabilities securityonline.info
- OffSeq radar entry radar.offseq.com
- ThreatINT CVE record cve.threatint.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 09:31.
Original description (NVD)
An Improper Link Resolution Before File Access ('Link Following') vulnerability in the unauthenticated web server handlers in Juniper Networks Session Smart Router and Session Smart Conductor allows a local unprivileged user to overwrite arbitrary files as root via unauthenticated API endpoints. This vulnerability can be exploited on Mist-managed routers and on unmanaged Routers that have not yet been onboarded to a Conductor. Routers already managed by Conductor are not affected.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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