Red Hat Keycloak CVE-2026-9791

Exploitation requires the attacker to be an authenticated Keycloak user with pre-existing organization membership - anonymous or newly created users without prior org enrollment cannot trigger this flaw. The Organizations feature must have been previously enabled and the user enrolled, then an administrator must have subsequently disabled the Organizations feature intending to revoke org-based access; the flaw manifests precisely in this post-disable state. Exploitation occurs via the account API or by requesting an OIDC token with the 'organization' scope included. Per CVSS PR:L, low-privilege authenticated access is sufficient - no administrative role is required. Factors that limit exploitation: requires valid credentials (not unauthenticated per PR:L), requires prior organizational membership enrollment, and the downstream impact depends on whether resource servers actually consume and act on organization claims in tokens.

The CVSS 3.1 vector AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N reflects a network-reachable, low-complexity exploit requiring only low-privileged authenticated access with no user interaction, limited to a confidentiality impact and no scope change. The base score of 4.3 (Medium) is consistent with an information disclosure issue rather than a critical compromise path. However, the real-world risk is context-dependent: if downstream resource servers rely on the 'organization' claim in tokens to gate access to sensitive resources, the incorrect claim could elevate the effective impact beyond what CVSS captures - essentially acting as an authorization bypass within the resource server's logic. No EPSS data was provided, so exploitation probability cannot be quantified. The vulnerability is not listed in CISA KEV, and no POC has been identified at time of analysis. The limiting factor - requirement for an authenticated user who has pre-existing organization membership - substantially reduces the exploitable population compared to an unauthenticated vector. Organizations that have disabled the Organizations feature specifically to revoke org-based access controls face the highest residual risk.

An authenticated user who was previously enrolled in a Keycloak organization - before an administrator disabled the Organizations feature - sends an OIDC token request to the Keycloak token endpoint including 'organization' in the requested scopes. Despite the feature being administratively disabled, Keycloak returns a token containing organization metadata claims. The user presents this token to a resource server that evaluates the 'organization' claim to determine access rights, causing the resource server to grant access based on organizational membership that the administrator intended to revoke. No public POC code has been identified, but the attack is straightforward for any user who retains their prior organization membership state.