CVE-2026-31847: Nexxtsolutions NEBULA300PLUS Firmware

High severity, CVSS 8.8. EPSS: 0.7% chance of exploitation in the next 30 days.

Hidden functionality in the /goform/setSysTools endpoint in Nexxt Solutions Nebula 300+ firmware through version 12.01.01.37 allows remote enablement of a Telnet service. By sending a crafted POST request with parameters such as telnetManageEn=true and telnetPwd, an authenticated attacker can activate a Telnet service on port 23.

Affected products

• Nexxtsolutions NEBULA300PLUS Firmware: up to and including 12.01.01.37

Published 2026-03-23. Last modified 2026-08-10.