CVE-2023-43742: Zultys Mx-E Firmware

Critical severity, CVSS 9.8. EPSS: 0.9% chance of exploitation in the next 30 days.

An authentication bypass in Zultys MX-SE, MX-SE II, MX-E, MX-Virtual, MX250, and MX30 with firmware versions prior to 17.0.10 patch 17161 and 16.04 patch 16109 allows an unauthenticated attacker to obtain an administrative session via a protection mechanism failure in the authentication function. In normal operation, the Zultys MX Administrator Windows client connects to port 7505 and attempts authentication, submitting the administrator username and password to the server. Upon authentication failure, the server sends a login failure message prompting the client to disconnect. However, if the client ignores the failure message instead and attempts to continue, the server does not forcibly close the connection and processes all subsequent requests from the client as if authentication had been successful.

Affected products

• Zultys Mx-E Firmware: before 16.0.4 (fixed in 16.0.4); from 17.0.6, before 17.0.10 (fixed in 17.0.10)
• Zultys Mx-SE Firmware: before 16.0.4 (fixed in 16.0.4); from 17.0.6, before 17.0.10 (fixed in 17.0.10)
• Zultys Mx-SE Ii Firmware: before 16.0.4 (fixed in 16.0.4); from 17.0.6, before 17.0.10 (fixed in 17.0.10)
• Zultys Mx-Virtual Firmware: before 16.0.4 (fixed in 16.0.4); from 17.0.6, before 17.0.10 (fixed in 17.0.10)
• Zultys MX250 Firmware: before 16.0.4 (fixed in 16.0.4); from 17.0.6, before 17.0.10 (fixed in 17.0.10)
• Zultys MX30 Firmware: before 16.0.4 (fixed in 16.0.4); from 17.0.6, before 17.0.10 (fixed in 17.0.10)

Published 2023-12-08. Last modified 2026-06-17.