Is there a public exploit for CVE-2026-103409?

Yes. Proof-of-concept code for CVE-2026-103409 has been published publicly.

How severe is CVE-2026-103409?

CVE-2026-103409 scores CVSS 9.8 (v3.1), rated critical.

9.8 Critical

A Missing authentication for critical function vulnerability in Juniper Networks Session Smart Router allows an unauthenticated…

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.

Proof-of-concept code is published

Public PoC

Public PoCListed proof-of-concept repositories

Signals come from Exploit-DB, Metasploit, Nuclei and published proof-of-concept repositories. Their absence means nothing was found, not that nothing exists.

Assessment

CVSS: 9.8 (v3.1)
Severity: Critical
Known exploited: Not listed in CISA KEV
Exploit availability: Public PoC
Published: 28 October 2026
Last updated: 28 October 2026
Weakness: CWE-306
Assigner: sirt@juniper.net

CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

At the source

References

https://supportportal.juniper.net/JSA112183

Community proofs of concept

No community proof of concept yet. If you have one for a published vulnerability and the right to share it, add it below — it will appear here once reviewed.

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