CVE-2021-4133

HIGHNVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.8 under NVD CVSS v3. EPSS exploit probability: 1.3%, top 32% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 8.8Exploit: None knownExposed: 0

A fix is available — apply it.

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.

CVSS v3
8.8
EG Score
8.8(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity88% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
69%
KEV
Not listed

Published

January 25, 2022

Last Modified

November 21, 2024

Advisory Details (3)

Auto-updated Aug 9, 2026
Patch available. Sources: redhat, github.
github Patch Available

Incorrect authorization allows unpriviledged users to create other users · Advisory · keycloak/keycloak · GitHub

https://github.com/keycloak/keycloak/security/advisories/GHSA-83x4-9cwr-5487
generic

Incorrect authorization allows unpriviledged users to create other users · Issue #9247 · keycloak/keycloak · GitHub

https://github.com/keycloak/keycloak/issues/9247
redhat Patch Available

2033602 – (CVE-2021-4133) CVE-2021-4133 Keycloak: Incorrect authorization allows unpriviledged users to create other users

https://bugzilla.redhat.com/show_bug.cgi?id=2033602

Vendor Advisories for CVE-2021-4133(9)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(8)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatrh-sso-7/sso75-openshift-rhel8:7.5-152022-01-18redhat
redhatkeycloak-services2022-01-17redhat
redhatrh-sso7-keycloak-0:15.0.4-1.redhat_00001.1.el8sso2022-01-17redhat
redhatrh-sso7-keycloak-0:15.0.4-1.redhat_00001.1.el7sso2022-01-17redhat
redhatrh-sso-7/sso7-rhel8-operator-bundle:7.5.0-122022-01-05redhat
redhatrh-sso-7/sso7-rhel8-operator-bundle:7.5.0-112022-01-04redhat
redhatrh-sso7-keycloak-0:15.0.2-3.redhat_00002.1.el7sso2021-12-20redhat
redhatrh-sso7-keycloak-0:15.0.2-3.redhat_00002.1.el8sso2021-12-20redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
Maven(1)
PackageVulnerable rangeFixed inDependents
org.keycloak:keycloak-services1.0-alpha-1 ... 9.0.3 (129 versions)15.1.1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 6× in last 7d / 28× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 135 total refreshes for this CVE.

  1. 2026-08-25 13:46 UTCEPSS rescore
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  44. 2026-06-29 22:02 UTCOSV refresh
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  75. 2026-06-12 10:40 UTCOSV refresh

Frequently asked(5)

What is CVE-2021-4133?
CVE-2021-4133 is a high vulnerability published on January 25, 2022. 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.
When was CVE-2021-4133 disclosed?
CVE-2021-4133 was first published in the National Vulnerability Database on January 25, 2022, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-4133 actively exploited?
CVE-2021-4133 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 30.7% of all scored CVEs.
What is the CVSS score of CVE-2021-4133?
CVE-2021-4133 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2021-4133?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-4133, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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