---
title: "CVE-2026-103411: Juniper Networks Session Smart Router - Integer Underflow"
description: "Juniper Networks Session Smart Router contains an integer underflow caused by improper handling in DhcpMessageDecoder, letting attackers with local network access cause information disclosure and denial of service via malicious DHCP reply."
url: https://panop.io/threat-heartbeat/CVE-2026-103411/
---

# CVE-2026-103411 Juniper Networks Session Smart Router - Integer Underflow

Juniper Networks Session Smart Router contains an integer underflow caused by improper handling in DhcpMessageDecoder, letting attackers with local network access cause information disclosure and denial of service via malicious DHCP reply.

CVSS base score 7.1 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-103411)

## Details

Type

Integer Underflow

Impact

Information Disclosure, Denial Of Service

CVSS vector

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

Published

28 October 2026

Updated

29 October 2026

Weakness

[CWE-191](https://cwe.mitre.org/data/definitions/191.html)

## Vendor fix

Update to the latest version of Juniper Networks Session Smart Router.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-103411](https://nvd.nist.gov/vuln/detail/CVE-2026-103411)
- [https://supportportal.juniper.net/JSA112183](https://supportportal.juniper.net/JSA112183)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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