Is CVE-2021-32637 actively exploited?

No active exploitation of CVE-2021-32637 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-32637 be exploited remotely?

Yes. CVE-2021-32637 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-32637?

CVE-2021-32637 has a CVSS score of 10.0 (CRITICAL).

HOME VULNERABILITIESCVE-2021-32637

CRITICAL

CVE-2021-32637

CWE-287Published: May 28, 2021· Updated: Jun 17, 2026

10.0

CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2021-32637 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 10.0.

The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.

From a weakness classification perspective (CWE-287): Authentication bypass vulnerabilities allow attackers to access protected resources without valid credentials.