CVE-2026-18215
Keycloak-services: keycloak-services: microsoft external access-token exchange bypasses configured tenant
- State
- Published
- Severity
- 6.8 Medium
- Published
- Jul 31, 2026
- Updated
- Sep 16, 2026
- Reserved
- Jul 29, 2026
Description
Keycloak provides a way to let users log in using Microsoft accounts while restricting access to a specific organization (tenant). A flaw was discovered where this restriction is ignored when using the token exchange feature. This means an attacker with a valid Microsoft token from a completely different organization could gain access to the Keycloak realm, potentially accessing sensitive data or performing unauthorized actions.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 6.8 Medium | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N | redhat |
Weaknesses
- CWE-287 Improper Authentication
Affected Products
| Product | Versions |
|---|---|
Red Hat build of Keycloak 26.6Red Hat |
|
Red Hat build of Keycloak 26.6Red Hat |
|
Red Hat build of Keycloak 26.6Red Hat |
|
Red Hat build of Keycloak 26.6.7Red Hat | |
Red Hat build of Keycloak 26.6.7Red Hat | |
Red Hat build of Keycloak 26.6.7Red Hat | |
Red Hat Data Grid 8Red Hat | |
Red Hat JBoss Enterprise Application Platform Expansion PackRed Hat | |
Red Hat Single Sign-On 7Red Hat |
References
- RHSA-2026:68277vendor-advisory
- RHSA-2026:68278vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-18215vdb-entry
- RHBZ#2508309issue-tracking
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