CVE-2026-9099: Authorization Bypass Through User-Controlled Key in Red Hat Red Hat build of Keycloak 26.4
A flaw was found in Keycloak. A missing authorization check in the GroupResource.addChild() endpoint within the Admin REST API allows an authenticated user with limited administrative privileges to reparent any existing group. When Fine-Grained Admin Permissions v2 (FGAPv2) is enabled, an attacker with management rights over a single low-privilege group can reparent a highly privileged group (such as one possessing the realm-admin role) under their managed group. Because group permissions follow a hierarchical structure, this action unauthorizedly grants the attacker management and password-reset capabilities over the members of the targeted privileged group. An attacker can exploit this to reset an administrator's password, compromise the account, and achieve a full realm takeover, leading to a complete compromise of confidentiality, integrity, and availability.
AI Analysis
Technical Summary
The vulnerability CVE-2026-9099 in Red Hat build of Keycloak 26.4 arises from a missing authorization check in the GroupResource.addChild() endpoint of the Admin REST API. This flaw allows an authenticated user with limited administrative privileges to reparent any existing group. Specifically, when Fine-Grained Admin Permissions v2 (FGAPv2) is enabled, an attacker with management rights over a low-privilege group can reparent a highly privileged group (e.g., one with realm-admin role) under their group. Because group permissions are hierarchical, this unauthorized reparenting grants the attacker management and password-reset capabilities over members of the privileged group. Exploitation can lead to resetting an administrator's password and achieving full realm takeover, compromising the system's confidentiality, integrity, and availability. The CVSS v3.1 score is 7.7 (high severity) with network attack vector, high complexity, high privileges required, no user interaction, and scope changed. Red Hat advisories acknowledge this vulnerability but do not currently list a specific patch or fix for it in the 26.4.13 update. Users should follow Red Hat's security advisories for remediation updates.
Potential Impact
An attacker with limited administrative privileges can escalate their rights by reparenting a highly privileged group under their control, thereby gaining management and password-reset capabilities over privileged users. This can lead to resetting administrator passwords and full compromise of the Keycloak realm, affecting confidentiality, integrity, and availability of the authentication system.
Mitigation Recommendations
Red Hat has published security advisories including this vulnerability in the Red Hat build of Keycloak 26.4.13 update. However, no explicit patch or fix for CVE-2026-9099 is currently listed in the advisories. Users should monitor the Red Hat Customer Portal and official advisories for updates and apply any forthcoming patches promptly. Prior to applying updates, back up existing installations, including applications, configuration files, and databases. Until a fix is available, restrict administrative privileges and monitor for suspicious group reparenting activities if possible.
CVE-2026-9099: Authorization Bypass Through User-Controlled Key in Red Hat Red Hat build of Keycloak 26.4
Description
A flaw was found in Keycloak. A missing authorization check in the GroupResource.addChild() endpoint within the Admin REST API allows an authenticated user with limited administrative privileges to reparent any existing group. When Fine-Grained Admin Permissions v2 (FGAPv2) is enabled, an attacker with management rights over a single low-privilege group can reparent a highly privileged group (such as one possessing the realm-admin role) under their managed group. Because group permissions follow a hierarchical structure, this action unauthorizedly grants the attacker management and password-reset capabilities over the members of the targeted privileged group. An attacker can exploit this to reset an administrator's password, compromise the account, and achieve a full realm takeover, leading to a complete compromise of confidentiality, integrity, and availability.
CVSS v3.1
Score 7.7high
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability CVE-2026-9099 in Red Hat build of Keycloak 26.4 arises from a missing authorization check in the GroupResource.addChild() endpoint of the Admin REST API. This flaw allows an authenticated user with limited administrative privileges to reparent any existing group. Specifically, when Fine-Grained Admin Permissions v2 (FGAPv2) is enabled, an attacker with management rights over a low-privilege group can reparent a highly privileged group (e.g., one with realm-admin role) under their group. Because group permissions are hierarchical, this unauthorized reparenting grants the attacker management and password-reset capabilities over members of the privileged group. Exploitation can lead to resetting an administrator's password and achieving full realm takeover, compromising the system's confidentiality, integrity, and availability. The CVSS v3.1 score is 7.7 (high severity) with network attack vector, high complexity, high privileges required, no user interaction, and scope changed. Red Hat advisories acknowledge this vulnerability but do not currently list a specific patch or fix for it in the 26.4.13 update. Users should follow Red Hat's security advisories for remediation updates.
Potential Impact
An attacker with limited administrative privileges can escalate their rights by reparenting a highly privileged group under their control, thereby gaining management and password-reset capabilities over privileged users. This can lead to resetting administrator passwords and full compromise of the Keycloak realm, affecting confidentiality, integrity, and availability of the authentication system.
Mitigation Recommendations
Red Hat has published security advisories including this vulnerability in the Red Hat build of Keycloak 26.4.13 update. However, no explicit patch or fix for CVE-2026-9099 is currently listed in the advisories. Users should monitor the Red Hat Customer Portal and official advisories for updates and apply any forthcoming patches promptly. Prior to applying updates, back up existing installations, including applications, configuration files, and databases. Until a fix is available, restrict administrative privileges and monitor for suspicious group reparenting activities if possible.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- redhat
- Date Reserved
- 2026-05-20T15:12:25.740Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-9099","vendor":"Red Hat"}]
Threat ID: 6a3d5b514853345fc13372d1
Added to database: 06/25/2026, 16:46:09 UTC
Last enriched: 07/15/2026, 09:43:05 UTC
Last updated: 08/08/2026, 12:41:12 UTC
Views: 129
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