CVE intelligence and bounded remediation

CVE-2021-26637 — Shinasys Sihas Sgw-300 Firmware security vulnerability

Critical CVSS 9.8

There is no account authentication and permission check logic in the firmware and existing apps of SiHAS's SGW-300, ACM-300, GCM-300, so unauthorized users can remotely control the device.

Severity
Critical
CVSS
9.8 (3.1)
Published
2022-06-23
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-287, CWE-306, CWE-862

Affected products

  • shinasys / sihas_sgw-300_firmware
  • shinasys / sihas_acm-300_firmware
  • shinasys / sihas_gcm-300_firmware

Showing 3 representative product identities from 6 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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