CVE-2021-40856 — Auerswald COMfortel 1400 IP and 2600 IP before 2.8G devices allow Authentication Bypass via the /about/../ substring

Matched remediation archetype

Authentication bypass and missing authentication

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

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.