CVE-2021-4133

mediumpriority · track · 35OT risk · elevatedEPSS 0.014 · 72 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.37% (72nd) EPSS

CVSS 6.5 · medium

Is it mine?

3 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-27

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

Technical severity, 0–10. One row per scoring source.

8.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.5–8.8

v2.06.5mediumAV:N/AC:L/Au:S/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 8 · impact 6.4

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 2.8 · impact 5.9

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · OSV

v3.18.1highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-863USprimaryCWE-863US

affected products (3)

Products and version ranges known to be affected.

n/a KeyCloak≤ keycloak 15.1.1enisa_euvdEU
redhat keycloak12.0.0 → 15.1.1nvdUScpe:2.3:a:redhat:keycloak:*:*:*:*:*:*:*:*
Maven org.keycloak:keycloak-services< 15.1.1osvUSpkg:maven/org.keycloak/keycloak-services

advisories (1)

Vendor and ecosystem advisories describing this.

GHSA-83x4-9cwr-5487Improper Authorization in Keycloak2022-01-06ghsa · osvUS
A incorrect authorization flaw was found in Keycloak 12.0.0, the flaw allows an attacker with any existing user account to create new default user accounts via the administrative REST API even where new user registration is disabled.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2022-01-25modified 2026-06-17

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+5004 more

references (26)

External citations — patches, advisories, analysis.

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