Description
A flaw was found in the group policy evaluation logic of Keycloak, an identity and access management solution. When a group policy is set to extend permissions to child groups, the system incorrectly uses a simple text-based prefix check to verify group membership. This allows a user who belongs to a different group with a similar starting name to bypass security checks and gain unauthorized access to administrative functions or protected resources.
Published: 2026-07-31
Score: 6.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

Vendor Workaround

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.

Tracking

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History

Sun, 02 Aug 2026 21:00:00 +0000

Type Values Removed Values Added
First Time appeared Redhat build Of Keycloak
Redhat data Grid
Redhat jboss Enterprise Application Platform Expansion Pack
Redhat single Sign On
Vendors & Products Redhat build Of Keycloak
Redhat data Grid
Redhat jboss Enterprise Application Platform Expansion Pack
Redhat single Sign On

Sat, 01 Aug 2026 00:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Sat, 01 Aug 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Fri, 31 Jul 2026 07:30:00 +0000

Type Values Removed Values Added
Description A flaw was found in the group policy evaluation logic of Keycloak, an identity and access management solution. When a group policy is set to extend permissions to child groups, the system incorrectly uses a simple text-based prefix check to verify group membership. This allows a user who belongs to a different group with a similar starting name to bypass security checks and gain unauthorized access to administrative functions or protected resources.
Title Keycloak-services: keycloak-services: group policy extendchildren matches sibling group path prefixes
First Time appeared Redhat
Redhat build Keycloak
Redhat jboss Data Grid
Redhat jbosseapxp
Redhat red Hat Single Sign On
Weaknesses CWE-863
CPEs cpe:/a:redhat:build_keycloak:
cpe:/a:redhat:jboss_data_grid:8
cpe:/a:redhat:jbosseapxp
cpe:/a:redhat:red_hat_single_sign_on:7
Vendors & Products Redhat
Redhat build Keycloak
Redhat jboss Data Grid
Redhat jbosseapxp
Redhat red Hat Single Sign On
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N'}


Subscriptions

Redhat Build Keycloak Build Of Keycloak Data Grid Jboss Data Grid Jboss Enterprise Application Platform Expansion Pack Jbosseapxp Red Hat Single Sign On Single Sign On
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-07-31T23:20:33.733Z

Reserved: 2026-07-29T07:49:19.596Z

Link: CVE-2026-18203

cve-icon Vulnrichment

Updated: 2026-07-31T23:20:29.361Z

cve-icon NVD

Status : Analyzed

Published: 2026-07-31T08:16:27.010

Modified: 2026-08-07T14:56:33.153

Link: CVE-2026-18203

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-07-28T13:44:55Z

Links: CVE-2026-18203 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-04T11:30:07Z

Weaknesses