Severity by source
AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Sub-admin credential required (PR:H), admin console exposed over network (AV:N); no availability impact is described or implied in the group-assignment attack path.
Primary rating from Vendor (redhat).
CVSS VectorNVD
Lifecycle Timeline
5DescriptionNVD
A flaw was found in the user creation component of Keycloak when Fine-Grained Admin Permissions V2 (FGAP V2) is enabled. This issue allows a sub-administrator with permission to create users to add those users to any group, even groups the sub-administrator is not authorized to manage. This could lead to unauthorized access to sensitive information or elevated privileges for the newly created users.
AnalysisAI
Privilege escalation in Red Hat Build of Keycloak's user creation component exposes environments running Fine-Grained Admin Permissions V2 (FGAP V2) to unauthorized group assignment by scoped sub-administrators. A sub-admin holding only user-create permissions can bypass group-level authorization checks and enroll newly created users into any group - including privileged or sensitive ones - well beyond the sub-admin's delegated scope. SSVC rates technical impact as total and no public exploit has been identified, though the EPSS score of 0.24% (15th percentile) and SSVC exploitation status of 'none' indicate low immediate exploitation likelihood.
Technical ContextAI
Keycloak is Red Hat's open-source identity and access management platform implementing OAuth 2.0, OpenID Connect, and SAML. Fine-Grained Admin Permissions V2 (FGAP V2) is a delegation feature that allows realm administrators to create scoped sub-administrator roles with bounded permissions - such as permitting a sub-admin to create users but not manage certain groups. The root cause is CWE-862 (Missing Authorization): the user creation workflow fails to enforce group-scope authorization when assigning group memberships, allowing the group-write operation to proceed without validating whether the calling sub-admin holds authorization over the target group. CPE data confirms the flaw spans Red Hat Build of Keycloak, Red Hat Data Grid 8 (which integrates Keycloak for SSO), Red Hat JBoss EAP Expansion Pack, and Red Hat Single Sign-On 7.
RemediationAI
Consult the Red Hat security advisory at https://access.redhat.com/security/cve/CVE-2026-18571 for patched package versions - exact fix versions are not confirmed in the available data and should not be inferred. As an immediate compensating control, disable Fine-Grained Admin Permissions V2 (FGAP V2) if not operationally required; this eliminates the vulnerable code path entirely but removes delegated admin granularity, requiring affected organizations to revert to realm-level administration. If FGAP V2 must remain enabled, audit all group memberships of users created since FGAP V2 was activated, revoke any unauthorized group assignments, and restrict sub-administrator accounts to the narrowest possible permission sets pending patch application. Monitor Bugzilla #2509759 for patch release status.
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Same weakness CWE-862 – Missing Authorization
View allSame technique Authentication Bypass
View allVendor StatusVendor
Debian
Bug #1088287| Release | Status | Fixed Version | Urgency |
|---|---|---|---|
| open | - | - |
Share
External POC / Exploit Code
Leaving vuln.today
EUVD-2026-51925
GHSA-5vmc-qhfj-qxc3