LANTRONIX XPress-DR Missing Authentication Flaw (CVE-2026-109439) Rated CVSS 9.3
A newly published critical vulnerability in LANTRONIX XPress-DR carries a CVSS score of 9.3. Here is what is affected and how to respond.
Key points
- CVE-2026-109439 affects LANTRONIX XPress-DR.
- CVSS 9.3 (Critical).
- No exploitation confirmed yet.
A critical missing authentication tracked as CVE-2026-109439 has been published in the National Vulnerability Database for LANTRONIX XPress-DR, with a CVSS base score of 9.3.
At a glance
- CVE
- CVE-2026-109439
- Product
- LANTRONIX XPress-DR
- CVSS
- 9.3 Critical
- Weakness
- missing authentication
- Exploited
- No known exploitation
What is the vulnerability?
The NVD entry states: Lantronix XPress-DR and XPress-DR-I (CoBos-family) firmware through 8.1.0.0 contains a missing authentication vulnerability that allows remote attackers to read and persistently overwrite device configuration by sending crafted frames to the unauthenticated UDP configuration protocol on port 30718. Attackers can send a type 0xF8 query to read live configuration data and a type 0xFD frame with exactly 0x78 body bytes to rewrite the device IP address and serial-channel forwarding records, causing changes to commit to EEPROM and persist across reboots. The XPress-DR product series reached end-of-life/end-of-support in February 2025.
Affected versions
| Vendor | Product | Versions |
|---|---|---|
| Lantronix | XPress-DR | up to 8.1.0.0 |
| Lantronix | XPress-DR-I | up to 8.1.0.0 |
Is it being exploited?
There is no public confirmation of exploitation at the time of publication. It does not appear in CISA's Known Exploited Vulnerabilities catalog. We will update this report if that changes.
What should you do?
- Identify whether the affected product and versions run in your environment.
- Apply the vendor update listed in the advisory as soon as it is available.
- Limit network exposure of the affected service until it is patched.
- Monitor the vendor advisory for updated guidance or exploitation reports.
What to do and how to stay safe: CVE-2026-109439
- Vulnerability severity scores ignore your specific architecture and context.
- Exploitability depends on network exposure and user behavior, not just code flaws.
- Prioritization requires continuous asset inventory and threat intelligence alignment.
Risk-based vulnerability management focuses your limited resources on the flaws that actually threaten your business. Start by mapping your critical assets and checking for active exploits to prioritize your backlog.
Step-by-step guide: Risk-Based Vulnerability Management: Prioritize Fixes by Actual Danger
General security guidance from the Threat Times newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
What is CVE-2026-109439?
CVE-2026-109439 is a missing authentication vulnerability in LANTRONIX XPress-DR.
How severe is CVE-2026-109439?
It has a CVSS score of 9.3 Critical.
Is CVE-2026-109439 being exploited?
There is no public confirmation of exploitation at the time of publication.
