CVE intelligence and bounded remediation

CVE-2021-21335 — Spnego Http Authentication Module Project Spnego Http Authentication Mo… security vulnerability

Critical CVSS 9.8

In the SPNEGO HTTP Authentication Module for nginx (spnego-http-auth-nginx-module) before version 1.1.1 basic Authentication can be bypassed using a malformed username. This affects users of spnego-http-auth-nginx-module that have enabled basic authentication. This is fixed in version 1.1.1 of spnego-http-auth-nginx-module. As a workaround, one may disable basic authentication.

Severity
Critical
CVSS
9.8 (3.1)
Published
2021-03-08
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-287

Affected products

  • spnego_http_authentication_module_project / spnego_http_authentication_module

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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