SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2026-31847

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.

HIGH 8.5EPSS 0.42%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.42%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

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.

CVSS 4.0
8.5 HIGHCVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS
0.42% probability · 36th percentile
CISA KEV
Not listed
Weakness
CWE-912
Affected
nexxtsolutions/nebula300plus firmware
Source
309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.