Keycloak: UMA Policy Resource Injection Allows Unauthorized Cross-User Permission Grants
A flaw was found in Keycloak. An authenticated user with the uma_protection role can bypass User-Managed Access (UMA) policy validation. This allows the attacker to include resource identifiers owned by other users in a policy creation request, even if the URL path specifies an attacker-owned resource. Consequently, the attacker gains unauthorized permissions to victim-owned resources, enabling them to obtain a Requesting Party Token (RPT) and access sensitive information or perform unauthorized actions.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.keycloak:keycloak-services | < 26.5.7 | 26.5.7 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-4636
- https://github.com/keycloak/keycloak/issues/47717
- https://github.com/keycloak/keycloak/commit/995832f8b74b02833d106c8788bb7a78634aa725
- https://access.redhat.com/errata/RHSA-2026:6475
- https://access.redhat.com/errata/RHSA-2026:6476
- https://access.redhat.com/errata/RHSA-2026:6477
- https://access.redhat.com/errata/RHSA-2026:6478
- https://access.redhat.com/security/cve/CVE-2026-4636
- https://bugzilla.redhat.com/show_bug.cgi?id=2450251
- https://github.com/keycloak/keycloak
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N- Weakness (CWE)
CWE-551- Platform
- Java / Kotlin (Maven)
- Package
org.keycloak:keycloak-services- Disclosed
- 02.04.2026
- Updated
- 11.10.2026 13:20
Sources and licenses
OSV / GitHub Advisory Database - GHSA-f2hx-5fx3-hmcv - CC BY 4.0
Vulnerability history: org.keycloak:keycloak-services
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 98
- First → latest
- 01.2022 08.2026
- Without a fix
- 16
- Exploited in attacks
- 0
Severity breakdown
- Critical 3
- High 26
- Medium 51
- Low 18
Disclosures per year
- 2022: 9
- 2023: 9
- 2024: 17
- 2025: 11
- 2026: 52
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Keycloak: UMA Policy Resource Injection Allows Unauthorized Cross-User Permission Grants this entry
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