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Fencer Vulns
high 8.8

CVE-2021-4133 json

Improper Authorization in Keycloak

published 2022-01-06 4 y ago modified 2026-07-16 3 mo ago also GHSA-83x4-9cwr-5487 , EUVD-2022-0514

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 72%
public exploits
0
none known

Summary

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.

Patch / fix

  • maven org.keycloak:keycloak-services 15.1.1
  • redhat keycloak 15.1.1
  • rh-sso7-keycloak red hat single sign on 7.5 15.0.4-1.redhat_00001.1.el7sso
  • rh-sso7-keycloak-server red hat single sign on 7.5 15.0.4-1.redhat_00001.1.el7sso
  • rh-sso7-keycloak red hat single sign on 7.5 15.0.4-1.redhat_00001.1.el8sso
  • rh-sso7-keycloak-server red hat single sign on 7.5 15.0.4-1.redhat_00001.1.el8sso
  • rh-sso7-keycloak red hat single sign on 7.5 15.0.2-3.redhat_00002.1.el7sso
  • rh-sso7-keycloak-server red hat single sign on 7.5 15.0.2-3.redhat_00002.1.el7sso
  • rh-sso7-keycloak red hat single sign on 7.5 15.0.2-3.redhat_00002.1.el8sso
  • rh-sso7-keycloak-server red hat single sign on 7.5 15.0.2-3.redhat_00002.1.el8sso

red hat advisories RHSA-2022:0151RHSA-2022:0152RHSA-2021:5218RHSA-2021:5219

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-4133 updated cvss 8.3

Keycloak: Incorrect authorization allows unpriviledged users to create other users

  • Red Hat Middleware Containers for OpenShift rh-sso-7/sso75-openshift-rhel8 7.5-11, rh-sso-7/sso75-openshift-rhel8 7.5-15, rh-sso-7/sso7-rhel8-operator-bundle 7.5.0-11, rh-sso-7/sso7-rhel8-operator-bundle 7.5.0-12
    fixed: vendor fix RHSA-2022:0015
  • Red Hat Single Sign-On 7.5 for RHEL 7 Server rh-sso7-keycloak 15.0.2-3.redhat_00002.1.el7sso, rh-sso7-keycloak 15.0.4-1.redhat_00001.1.el7sso, rh-sso7-keycloak-server 15.0.2-3.redhat_00002.1.el7sso, rh-sso7-keycloak-server 15.0.4-1.redhat_00001.1.el7sso
    fixed: vendor fix RHSA-2021:5218
  • Red Hat Single Sign-On 7.5 for RHEL 8 rh-sso7-keycloak 15.0.2-3.redhat_00002.1.el8sso, rh-sso7-keycloak 15.0.4-1.redhat_00001.1.el8sso, rh-sso7-keycloak-server 15.0.2-3.redhat_00002.1.el8sso, rh-sso7-keycloak-server 15.0.4-1.redhat_00001.1.el8sso
    fixed: vendor fix RHSA-2021:5219
  • Red Hat RHSSO 7.5 async for CVE-2021-4133
    fixed: vendor fix RHSA-2021:5217
  • Red Hat RHSSO 7.5.1
    fixed: vendor fix RHSA-2022:0155
  • Red Hat A-MQ Online keycloak-services
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.37% chance of exploitation in the next 30 days, higher than 72% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.5 AV:N/AC:L/Au:S/C:P/I:P/A:P
GitHub 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
maven org.keycloak:keycloak-services
<15.1.1
15.1.1

Affected products

  • n/a Keycloak

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.