CVE-2026-109439

Lantronix XPress-DR 8.1.0.0 Unauthenticated Configuration Write via UDP 30718

Published Oct 14, 2026 CVSS 4.0 · 9.3 Critical EPSS < 1% KEV · Not listed
Description
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.

Remediation

Vendor Workaround

To mitigate this vulnerability, connect to the device via Telnet or CLI, open the Security settings (option 6), set “Disable port 77FEh” to Y, then save and exit to disable port 30718 (77FEh).

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Lantronix
Lantronix xpress-dr
Lantronix xpress-dr-i
Vendors & Products Lantronix
Lantronix xpress-dr
Lantronix xpress-dr-i
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title Lantronix XPress-DR 8.1.0.0 Unauthenticated Configuration Write via UDP 30718
Weaknesses CWE-306
References
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 9.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Oct 16, 2026, 5:15 PM
Reserved
Oct 12, 2026, 3:52 PM
Status
Awaiting Analysis
Published
Oct 14, 2026, 5:18 PM
Modified
Oct 16, 2026, 7:00 PM