U.S. flag   An official website of the United States government
Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock (Dot gov) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

CVE-2026-48794 Detail

Description

Authelia is an open-source authentication and authorization server providing two-factor authentication and single sign-on (SSO) for applications via a web portal. In versions 4.36.0 through 4.39.19, due to lack of canonicalization of domains in very specific edge cases, an access control rule may be skipped when it should match a request. The specific conditions that could lead to a security issue for vulnerability are: 1. The specific target resource of the attack must be using the forwarded authorization integration; 2. The requested domain must have two additional segments compared to a session domain i.e. `a.b.example.com` is requested, but the session domain is `example.com`; 3. There access control rules must specify two separate rules which both contain inexact domain matches such as `*.b.example.com` and `*.example.com` i.e. wildcards, username matches, group matches; 4. The rules must be in order of most specific domain to least specific domain; 5. The second rule must be more permissive than the first rule; 6. The attacker must specifically request a URL for the more specific domain, with the second part containing one or more capitalized letters i.e. `https://a.B.example.com` and no other segment with capitalized letters; 7. The integration used must not be the Envoy ExtAuthz integration; and 8. The proxy must not canonicalize the requested host name in the relevant header before sending it to the relevant authorization endpoint. The kind of configuration used to produce this issue and result in a `bypass` rule being matched has long been highly discouraged. Essentially hosts which should be bypassed entirely should not be secured by having the proxy check them with the authorization handlers. Upgrade to 4.39.20 to receive a patch.


Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
CVSS-BT 1.3 LOW
Vector:  CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N/E:P

References to Advisories, Solutions, and Tools

By selecting these links, you will be leaving NIST webspace. We have provided these links to other web sites because they may have information that would be of interest to you. No inferences should be drawn on account of other sites being referenced, or not, from this page. There may be other web sites that are more appropriate for your purpose. NIST does not necessarily endorse the views expressed, or concur with the facts presented on these sites. Further, NIST does not endorse any commercial products that may be mentioned on these sites. Please address comments about this page to [email protected].

URL Source(s) Tag(s)
GitHub, Inc.
GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-178 Improper Handling of Case Sensitivity GitHub, Inc.  
CWE-863 Incorrect Authorization GitHub, Inc.  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-48794
NVD Published Date:
06/19/2026
NVD Last Modified:
06/19/2026
Source:
GitHub, Inc.