What is CVE-2026-18203?

CVE-2026-18203 is a medium-severity vulnerability in Red Hat Build Of Keycloak, classified under Incorrect Authorization. CVSS score: 6.5/10. Published 2026-07-31.

How severe is CVE-2026-18203?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Auth bypass in Red Hat Build Of Keycloak

CVE-2026-18203

A flaw was found in the group policy evaluation logic of Keycloak, an identity and access management solution. When a group policy is set to extend permissions to child groups, the system incorrectly uses a simple text-based prefix check t…

Vulnerability class: Broken Access Control

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N.

Affected products

Red Hat Build Of Keycloak
Red Hat Data Grid 8
Red Hat Jboss Enterprise Application Platform Expansion Pack
Red Hat Single Sign-on 7

Weakness classification (CWE)

CWE-863 — Incorrect Authorization

References

secalert@redhat.com (x_refsource_REDHAT, vdb-entry)
secalert@redhat.com (x_refsource_REDHAT, issue-tracking)

Frequently asked questions

What is CVE-2026-18203?: CVE-2026-18203 is a medium-severity vulnerability in Red Hat Build Of Keycloak, classified under Incorrect Authorization. CVSS score: 6.5/10. Published 2026-07-31.
How severe is CVE-2026-18203?: Medium severity. CVSS v3 base score is 6.5 out of 10.