CVE-2021-3424 Keycloak is vulnerable to IDN homograph attack

What is CVE-2021-3424?

CVE-2021-3424 is a medium-severity authentication bypass vulnerability in Redhat Single Sign-On, published on 1 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A flaw was found in keycloak as shipped in Red Hat Single Sign-On 7.4 where IDN homograph attacks are possible. A malicious user can register himself with a name already registered and trick admin to grant him extra privileges.

Weakness: CWE-287

Which versions are affected by CVE-2021-3424?

2 open source packages ship an affected version, including org.keycloak:keycloak-services. It affects 1 product.

Products include Redhat Single Sign-On.

How do I fix CVE-2021-3424?

Upgrade org.keycloak:keycloak-services to 18.0.0 or later.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2021-3424 being exploited?

There is no known exploitation of CVE-2021-3424 in the wild and no public exploit code.

Other vulnerabilities in Redhat Single Sign-On

• CVE-2020-10695 Privilege escalation in containers/redhat-sso-7 High 7.8
• CVE-2022-2256 Keycloak vulnerable to Stored Cross site Scripting (XSS) when loading default roles Low 3.8
• CVE-2020-14341 Server-side request forgery in Red Hat Single Sign-On Low 2.7

All Redhat Single Sign-On vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-pf38-cw3p-22q9.