---
title: "CVE-2026-109439: Lantronix XPress-DR - Authentication Bypass"
description: "Lantronix XPress-DR and XPress-DR-I firmware through 8.1.0.0 contain a missing authentication vulnerability caused by unauthenticated UDP configuration protocol on port 30718, letting remote attackers read and overwrite device configuration persistently, exploit requires network access to UDP port 30718."
url: https://panop.io/threat-heartbeat/CVE-2026-109439/
---

# CVE-2026-109439 Lantronix XPress-DR - Authentication Bypass

Lantronix XPress-DR and XPress-DR-I firmware through 8.1.0.0 contain a missing authentication vulnerability caused by unauthenticated UDP configuration protocol on port 30718, letting remote attackers read and overwrite device configuration persistently, exploit requires network access to UDP port 30718.

CVSS base score 9.8 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-109439)

## Details

Type

Authentication Bypass

Impact

Information Disclosure, Data Tampering

CVSS vector

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

Published

14 October 2026

Updated

15 October 2026

Weakness

[CWE-306](https://cwe.mitre.org/data/definitions/306.html)

## Vendor fix

Update to the latest firmware version or contact vendor for patches; note product reached end-of-life in February 2025.

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-2026-109439](https://nvd.nist.gov/vuln/detail/CVE-2026-109439)
- [https://www.vulncheck.com/advisories/lantronix-xpress-dr-unauthenticated-configuration-write-via-udp-30718](https://www.vulncheck.com/advisories/lantronix-xpress-dr-unauthenticated-configuration-write-via-udp-30718)
- [https://cdn.lantronix.com/wp-content/uploads/pdf/PCN-753-Rev-B-EOL-Notice-XPRESS.pdf?xnotes\_\_c=I%20am%20interested%20in%20the%20XPress%20DR%20/%20XPress%20DR-IAP.](https://cdn.lantronix.com/wp-content/uploads/pdf/PCN-753-Rev-B-EOL-Notice-XPRESS.pdf?xnotes__c=I%20am%20interested%20in%20the%20XPress%20DR%20/%20XPress%20DR-IAP.)

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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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