Open Redirect in Authelia

CVE-2021-29456

Authelia is an open-source authentication and authorization server providing 2-factor authentication and single sign-on (SSO) for your applications via a web portal. In versions 4.27.4 and earlier, utilizing a HTTP query parameter an attacker is able to redirect users from the web application to any domain, including potentially malicious sites. This security issue does not directly impact the security of the web application itself. As a workaround, one can use a reverse proxy to strip the query parameter from the affected endpoint. There is a patch for version 4.28.0.

Vulnerability class: Open Redirect

EPSS: 0.005 (40.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.7 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-29456?
CVE-2021-29456 is a medium-severity vulnerability in Authelia, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 5.7/10. Published 2021-04-21.
How severe is CVE-2021-29456?
Medium severity. CVSS v3 base score is 5.7 out of 10.