---
id: CVE-2026-31847
title: >-
  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
summary: >-
  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
  telnetMa…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-912
vendor: nexxtsolutions
product: nebula300plus_firmware
affected:
  - nebula300plus_firmware <= 12.01.01.37
published: '2026-03-23'
updated: '2026-08-10'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-31847'
references:
  - url: >-
      https://nexxt-connectivity-frontend.s3.amazonaws.com/media/docs/Nebula300+_v12.01.01.37.zip
    label: 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c
  - url: 'https://www.nexxtsolutions.com/connectivity/internal-products/ARN02304U6/'
    label: 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c
tags:
  - nvd
epss: 0.00681
epssPercentile: 0.50391
ingestedAt: '2026-08-10T12:39:46.304Z'
---

## Overview

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

- `nebula300plus_firmware <= 12.01.01.37`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.