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.
Affected products
redhat: build of keycloak
References4
- access.redhat.com/security/cve/CVE-2026-18215 Vendor Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2508309 Issue TrackingVendor Advisory
- access.redhat.com/errata/RHSA-2026:68277
- access.redhat.com/errata/RHSA-2026:68278
Metrics
- CVSS 3.1
-
8.1
HIGH
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - EPSS — exploit probability
- 0% percentile: 35 · as of 13 November 2026
- CWE
- CWE-287
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.