CVE intelligence and bounded remediation

CVE-2021-20998 — Wago 0852-0303 Firmware security vulnerability

Critical CVSS 10

In multiple managed switches by WAGO in different versions without authorization and with specially crafted packets it is possible to create users.

Severity
Critical
CVSS
10 (3.1)
Published
2021-05-13
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-306

Affected products

  • wago / 0852-0303_firmware
  • wago / 0852-1305_firmware
  • wago / 0852-1505_firmware
  • wago / 0852-1305/000-001_firmware
  • wago / 0852-1505/000-001_firmware

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.

Authoritative sources

Complete CVE record and remediation plan

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