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Vulnerability record · CVE-2026-18215 · published 31 July 2026

CVE-2026-18215: Redhat build of keycloak improper authentication vulnerability

Redhat · Build Of Keycloak

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.

8.1 CVSS 3.1 High EPSS 0.40% · top 68.0% CWE-287 · Improper authentication
8.1CVSS 3.1 base score
0.40%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
16 Sep 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://access.redhat.com/errata/RHSA-2026:68277
https://access.redhat.com/errata/RHSA-2026:68278
https://access.redhat.com/security/cve/CVE-2026-18215 Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2508309 Issue TrackingVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-18215), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.