CVE-2026-18207: Keycloak-services: keycloak-services: client policy source-group condition bypass via duplicate group name matching

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 29 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

0.3%

EPSS score, percentile 24.3 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

6.5 Medium

CVSS v3.1 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 29 Oct 2026. About the data.

What to do

Workaround (from the CVE record)

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

This summary is based on the CVE record as of 29 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Versions not listed are: affected.

Versions not listed are: affected.

Versions not listed are: affected.

Versions not listed are: unaffected.

Versions not listed are: unaffected.

Versions not listed are: unaffected.

Source: CVE List, as of 29 Oct 2026. About the data.

About this vulnerability

A flaw was found in the client policy enforcement mechanism of Keycloak. The issue occurs when the system checks group membership by name instead of a unique identifier. An attacker with client management privileges could bypass security policies by joining a group with a matching name in a different part of the group hierarchy, potentially allowing them to register or update clients without foll…

Summary: CVE record, as of 29 Oct 2026.

• CISA has not added CVE-2026-18207 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
• The CVE record was published on 29 Jul 2026.
• The CVE record carries a CVSS v3.1 base score of 6.5 (Medium), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.3% (percentile 24.3), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
• CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact partial.
• The credits in the CVE record name OpenAI as finder.

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; CVE List, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026. About the data.

Description

Keycloak-services: keycloak-services: client policy source-group condition bypass via duplicate group name matching

A flaw was found in the client policy enforcement mechanism of Keycloak. The issue occurs when the system checks group membership by name instead of a unique identifier. An attacker with client management privileges could bypass security policies by joining a group with a matching name in a different part of the group hierarchy, potentially allowing them to register or update clients without following required security hardening profiles.

Source: CVE List, as of 29 Oct 2026. About the data.

Timeline

Known exploited Red Hat vulnerabilities

• CVE-2015-3246: Red Hat Libuser Race Condition Vulnerability (added 26 Aug 2026)
• CVE-2015-5287: Red Hat Automatic Bug Reporting Tool Privilege Escalation Vulnerability (added 26 Aug 2026)
• CVE-2018-14667: Red Hat JBoss RichFaces Framework Expression Language Injection Vulnerability (added 28 Sep 2023)
• CVE-2021-3560: Red Hat Polkit Incorrect Authorization Vulnerability (added 12 May 2023)
• CVE-2021-4034: Red Hat Polkit Out-of-Bounds Read and Write Vulnerability (added 27 Jun 2022)