CVE-2021-4133

Name: CVE-2021-4133
Creator: NVD / NIST
Published: 2022-01-25T20:15:08.607+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 1.35%

Last modified Jun 17, 2026

CVE-2021-4133 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. A flaw was found in Keycloak in versions from 12.0.0 and before 15.1.1 which allows an attacker with any existing user account to create new default user accounts via the administrative REST API even when new user registration is disabled.. EPSS estimates a 1.35% chance of exploitation in the next 30 days.

Description

A flaw was found in Keycloak in versions from 12.0.0 and before 15.1.1 which allows an attacker with any existing user account to create new default user accounts via the administrative REST API even when new user registration is disabled.

Metrics

CVSS 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

1.35%

67.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Redhat	Keycloak	>= 12.0.0, < 15.1.1

References

https://bugzilla.redhat.com/show_bug.cgi?id=2033602Issue Tracking, Third Party Advisory
https://github.com/keycloak/keycloak/issues/9247Third Party Advisory
https://github.com/keycloak/keycloak/security/advisories/GHSA-83x4-9cwr-5487Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.htmlNot Applicable
https://bugzilla.redhat.com/show_bug.cgi?id=2033602Issue Tracking, Third Party Advisory
https://github.com/keycloak/keycloak/issues/9247Third Party Advisory
https://github.com/keycloak/keycloak/security/advisories/GHSA-83x4-9cwr-5487Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.htmlNot Applicable

Timeline

Published: Jan 25, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-4133?

How severe is CVE-2021-4133?

CVE-2021-4133 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 1.35% probability of exploitation in the next 30 days.

How do I fix CVE-2021-4133?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-4133?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST