CVE-2026-31847

Hidden Functionality Enables Remote Telnet Activation via /goform/setSysTools in Nexxt Nebula 300+

Published Mar 23, 2026 CVSS 4.0 · 8.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
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. This exposes a privileged diagnostic interface that is not intended for external access and can be used to interact with the underlying system. 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.
Title Nexxt Nebula 300+ - Hidden Functionality Enables Remote Telnet Activation via /goform/setSysTools Hidden Functionality Enables Remote Telnet Activation via /goform/setSysTools in Nexxt Nebula 300+
Type Values Removed Values Added
Title Hidden Functionality Enables Remote Telnet Activation via /goform/setSysTools in Nexxt Nebula 300+ Nexxt Nebula 300+ - Hidden Functionality Enables Remote Telnet Activation via /goform/setSysTools
Type Values Removed Values Added
First Time appeared Nexxtsolutions nebula300plus
Nexxtsolutions nebula300plus Firmware
CPEs cpe:2.3:h:nexxtsolutions:nebula300plus:-:*:*:*:*:*:*:*
cpe:2.3:o:nexxtsolutions:nebula300plus_firmware:*:*:*:*:*:*:*:*
Vendors & Products Nexxtsolutions nebula300plus
Nexxtsolutions nebula300plus Firmware
Metrics cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
Metrics cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

cvssV4_0

{'score': 8.5, 'vector': 'CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Type Values Removed Values Added
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. Once enabled, the service exposes a privileged diagnostic management interface over the network, increasing the attack surface and enabling further compromise of the device. 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. This exposes a privileged diagnostic interface that is not intended for external access and can be used to interact with the underlying system.
Title Hidden functionality allows remote Telnet enablement in Nexxt Nebula 300+ Hidden Functionality Enables Remote Telnet Activation via /goform/setSysTools in Nexxt Nebula 300+
Metrics cvssV4_0

{'score': 8.5, 'vector': 'CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Type Values Removed Values Added
First Time appeared Nexxtsolutions
Nexxtsolutions nebula300+
Vendors & Products Nexxtsolutions
Nexxtsolutions nebula300+
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
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. Once enabled, the service exposes a privileged diagnostic management interface over the network, increasing the attack surface and enabling further compromise of the device.
Title Hidden functionality allows remote Telnet enablement in Nexxt Nebula 300+
Weaknesses CWE-912
References
Metrics cvssV4_0

{'score': 8.5, 'vector': 'CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
TuranSec
Published
Updated
Aug 10, 2026, 11:43 AM
Reserved
Mar 9, 2026, 6:20 PM
Status
Modified
Published
Mar 23, 2026, 1:16 PM
Modified
Aug 10, 2026, 12:17 PM