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Case File

CVE-2021-32637

CRITICAL · CVSS 10 EPSS 1.87% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2021-05-28 · Last synced 2026-08-04

CyberRota Analysis

This is a critical severity vulnerability with a CVSS score of 10.0. It affects Nginx. Public exploit code or proof-of-concept references have been detected in its references.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2021-32637
Severity
CRITICAL
CVSS
10
EPSS
1.87%
Nginx

Original NVD Description

Authelia is a a single sign-on multi-factor portal for web apps. This affects uses who are using nginx ngx_http_auth_request_module with Authelia, it allows a malicious individual who crafts a malformed HTTP request to bypass the authentication mechanism. It additionally could theoretically affect other proxy servers, but all of the ones we officially support except nginx do not allow malformed URI paths. The problem is rectified entirely in v4.29.3. As this patch is relatively straightforward we can back port this to any version upon request. Alternatively we are supplying a git patch to 4.25.1 which should be relatively straightforward to apply to any version, the git patches for specific versions can be found in the references. The most relevant workaround is upgrading. You can also add a block which fails requests that contains a malformed URI in the internal location block.

Related CVEs

Other vulnerabilities affecting the same vendor(s)