CVE-2026-9799
Description
A flaw was found in org.keycloak.authorization. An authenticated user with a granted User-Managed Access (UMA) permission ticket for one resource can exploit this by using a specific permission request prefix to bypass per-resource access control. This allows the user to gain unauthorized access to all resources of that type within the same resource server, even if they do not have a ticket for those specific resources. This vulnerability requires the resource server to be configured in PERMISSIVE policy enforcement mode and affects typed resources with ownerManagedAccess enabled, where no explicit policy protects the resource type. The primary consequence is unauthorized information disclosure or modification of resources.
Statement
A Medium severity flaw exists in Keycloak's authorization component where a user with a UMA permission ticket for a specific resource type can gain unauthorized access to all resources of that type. This bypass occurs when the resource server is configured with the non-default PERMISSIVE policy enforcement mode, has ownerManagedAccess enabled for typed resources, and lacks a covering policy for the resource type. Exploitation requires an authenticated user with an existing permission ticket, limiting its impact to specific, non-default Keycloak deployments.
Mitigation
To mitigate this issue, ensure that the Keycloak client's policy enforcement mode is set to ENFORCING instead of PERMISSIVE. The PERMISSIVE mode is a non-default configuration that enables the vulnerability. Changing this setting will prevent the unauthorized access to resources of the same type. Consult Keycloak documentation for specific instructions on configuring policy enforcement mode for your client. This change may require a restart or reload of the Keycloak service to take effect and could impact existing authorization policies if not carefully managed.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.6 | N/A | 4.6 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | Required | N/A | Required |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | Low | N/A | Low |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism
Access control checks for specific user data or functionality can be bypassed.
Access Control
Technical Impact: Gain Privileges or Assume Identity
Horizontal escalation of privilege is possible (one user can view/modify information of another user).
Access Control
Technical Impact: Gain Privileges or Assume Identity
Vertical escalation of privilege is possible if the user-controlled key is actually a flag that indicates administrator status, allowing the attacker to gain administrative access.
Acknowledgements
Red Hat would like to thank Omaroo Baniessa for reporting this issue.
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