by Kastro
Paper/Archive/CVE-2026-109439

CVE-2026-109439

LANTRONIX XPress-DR — Lantronix XPress-DR 8.1.0.0 Unauthenticated Configuration Write via UDP 30718

EPSS 0.6%CVSS 9.8
critical.is priorityof 100
39
CVSS 9.8 (CNA)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 49.5.495 × 209.9No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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

ProductAffectedFixed inSource
XPress-DR≤ 8.1.0.0–CNA
XPress-DR-I≤ 8.1.0.0–CNA

Scores by source

VulnCheck (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
VulnCheck (CNA)9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

advisorycdn.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.writeupvulncheck.com/advisories/lantronix-xpress-dr-unauthenticated-configuration-write-via-udp-30718