CVE intelligence and bounded remediation

CVE-2020-24987 — Tendacn Ac18 Firmware security vulnerability

Critical CVSS 9.8

Tenda AC18 Router through V15.03.05.05_EN and through V15.03.05.19(6318) CN devices could cause a remote code execution due to incorrect authentication handling of vulnerable logincheck() function in /usr/lib/lua/ngx_authserver/ngx_wdas.lua file if the administrator UI Interface is set to "radius".

Severity
Critical
CVSS
9.8 (3.1)
Published
2020-09-04
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-287

Affected products

  • tendacn / ac18_firmware

Showing 1 representative product identities from 2 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

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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