CVE-2021-32637

Critical

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.

SeverityCritical
CVSS10.0
Exploit probability—
ProductAuthelia
PublishedMay 28, 2021
First seenMay 28, 2021

How to fix

Update
  • authelia authelia4.25.1, 4.29.3 or later
  • github.com/authelia/authelia/v44.29.3 or later

Affected products

ProductAffected versionsFixed in
authelia authelia4.0.0 ≤ v < 4.25.1, 4.26.0 ≤ v < 4.29.34.25.1, 4.29.3
github.com/authelia/authelia/v4Go4.0.0-alpha1 ≤ v < 4.29.34.29.3

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.

CVE-2021-32637 · Authelia · Dark Radar