CVE-2026-9099
HIGH 7.7A 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.
Severe if exploited (CVSS 7.7), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.3%chance of exploitation in 30 days · 21st percentile
Impact if exploited
7.7CVSS 3.1 · HIGH
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityNone
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ⚠Privileges: Requires an admin / high-privilege account
- ✓User interaction: No user interaction needed
- ⚠Complexity: Needs a race window or specific setup
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-9099/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-9099/poc.json
Affected
Products Red Hat Build Of Keycloak 26.4 Red Hat Build Of Keycloak 26.4.13 Red Hat Build Of Keycloak 26.6 Red Hat Build Of Keycloak 26.6.4 Build Of Keycloak
Weakness (CWE)
- CWE-639: Authorization Bypass Through User-Controlled Key
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:N
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Redhat | Build Of Keycloak | ≥ 26.4 and < 26.4.13 |
| Redhat | Build Of Keycloak | ≥ 26.6 and < 26.6.4 |
All CVSS metrics
- HIGH 7.7 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:N - HIGH 7.7 v3.1 · ADP Primary
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:N - HIGH 7.7 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:N
References
Advisories
- https://access.redhat.com/errata/RHSA-2026:30049
- https://access.redhat.com/errata/RHSA-2026:30050
- https://access.redhat.com/errata/RHSA-2026:30083
- https://access.redhat.com/errata/RHSA-2026:30084
- https://access.redhat.com/security/cve/CVE-2026-9099
- https://bugzilla.redhat.com/show_bug.cgi?id=2480182
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-9099.json