CVE intelligence and bounded remediation

CVE-2025-52376 — An authentication bypass vulnerability in the /web/um_open_telnet.cgi endpoint in Nexxt Solutions NCM-X1800 Mesh Router firmware...

Critical CVSS 9.8

An authentication bypass vulnerability in the /web/um_open_telnet.cgi endpoint in Nexxt Solutions NCM-X1800 Mesh Router firmware UV1.2.7 and below, allowing an attacker to remotely enable the Telnet service without authentication, bypassing security controls. The Telnet server is then accessible with hard-coded credentials, allowing attackers to gain administrative shell access and execute arbitrary commands on the device.

Severity
Critical
CVSS
9.8 (3.1)
Published
2025-07-15
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-287, CWE-798

Affected products

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Matched remediation archetype

Authentication bypass and missing authentication

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Check exposure

  • Map every affected endpoint and protocol path, including alternate ports, legacy routes, recovery flows, service accounts, and machine-to-machine access.
  • Confirm which deployments enable the affected authentication mode and whether the interface is reachable from untrusted networks.
  • Review session, token, credential, and proxy trust configuration without attempting account takeover.

Remediate safely

  • Apply the supported fix and centralize fail-closed authentication before protected request handling.
  • Remove default or embedded credentials, rotate affected secrets and sessions, and bind authentication decisions to the intended audience and channel.
  • Add negative tests for alternate routes, malformed or absent credentials, recovery flows, and proxy-derived identity.

Authoritative sources

Complete CVE record and remediation plan

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