Bug 2501740 (CVE-2026-16108)

Summary: CVE-2026-16108 keycloak-services: keycloak-services: Realm default-group reads disclose hidden groups under FGAP v2
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: anujha, aschwart, asoldano, aszczucz, bbaranow, bmaxwell, boliveir, bstansbe, dlofthou, drichtar, istudens, ivassile, iweiss, mosmerov, mposolda, msvehla, nwallace, pberan, pesilva, pjindal, pmackay, rmartinc, rstancel, ssilvert, sthorger, thjenkin, vdosoudi, vmuzikar
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the default-groups REST endpoint and realm representation of Keycloak. This component is responsible for managing groups that are automatically assigned to new users within a realm. The issue allows a delegated administrator with realm-viewing permissions to see the names and identifiers of hidden default groups, even if they lack the specific permissions to view those groups. This can lead to the exposure of sensitive organizational structures or internal group names.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-07-17 14:55:00 UTC
A flaw was found in the Keycloak Admin REST API when Fine-Grained Admin Permissions (FGAP) v2 is enabled. The default-groups endpoint and the general realm representation do not correctly enforce per-group view permission checks for default groups. A delegated administrator who has been granted realm-level view permissions but is explicitly denied view permissions for specific groups can still enumerate those hidden groups. By accessing the admin/realms/{realm}/default-groups or admin/realms/{realm} endpoints, the attacker can recover group names, UUIDs, and paths. This allows an authenticated attacker to map out the authorization topology, including onboarding structures, privilege levels, or tenant information that should remain restricted.