Description
A flaw was found in the secure-client-uris client policy executor within Keycloak core services. This component is responsible for enforcing security requirements on client configurations, such as requiring encrypted connections for redirect URIs. Due to an improper check that only looks at the start of a web address rather than properly verifying the host, an attacker can bypass these security restrictions by using a specially crafted domain name. This could allow an attacker to intercept sensitive authentication codes over unencrypted connections.
Affected products
redhat: build of keycloak
References2
- access.redhat.com/security/cve/CVE-2026-18211 Vendor Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2508306 Issue TrackingVendor Advisory
Metrics
- CVSS 3.1
-
5.4
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N - EPSS — exploit probability
- 0% percentile: 24 · as of 13 November 2026
- CWE
- CWE-20
Could this be exploited in your environment?
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