CVE-2026-9099

CVE-2026-9099 is a high-severity vulnerability in Redhat Build Of Keycloak with a CVSS 3.x base score of 7.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-639.

Key facts

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.

Frequently asked questions

What is CVE-2026-9099?
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.
How severe is CVE-2026-9099?
CVE-2026-9099 has a CVSS 3.x base score of 7.7, rated high severity. It is exploitable over network with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-9099 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-9099?
CVE-2026-9099 affects Redhat Build Of Keycloak. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-9099?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-9099 have an EU (EUVD) identifier?
Yes. CVE-2026-9099 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39472.
When was CVE-2026-9099 published?
CVE-2026-9099 was published on 2026-06-25 and last updated on 2026-07-15.

References

Affected products (1)

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