CVE-2021-29456: medium-severity vulnerability in authelia
Authelia allows open redirects on the logout endpoint
Published · Updated
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.7epss 0.5%
exploitation probability
0.5%top 58% of all CVEs
observed exploitation
nono source reports it
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.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N
Affected products
authelia · autheliaRelated CVEs — authelia
In the same product, most dangerous first.
CVE-2021-32637CRITICALAuthentication bypassed with malformed request URIEPSS 1.9%CVE-2026-47203LOWAuthelia Missing Username Canonicalization in Basic Auth (LDAP)EPSS 0.5%CVE-2026-48794LOWAuthelia has an Edge Case Access Control Rule MismatchEPSS 0.4%CVE-2025-24806LOWRegulation applies separately to Username-based logins to Email-based logins in autheliaEPSS 0.4%CVE-2026-33525LOWAuthelia: Improper Neutralization of Input During Web Page Generation Leads to Potential Cross-site ScriptingEPSS 0.3%