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.

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Advisories

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Fixes

Solution

No solution given by the vendor.


Workaround

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

History

Sun, 02 Aug 2026 19:45:00 +0000

Type Values Removed Values Added
First Time appeared Redhat build Of Keycloak
Redhat data Grid
Redhat jboss Enterprise Application Platform Expansion Pack
Redhat single Sign-on
Vendors & Products Redhat build Of Keycloak
Redhat data Grid
Redhat jboss Enterprise Application Platform Expansion Pack
Redhat single Sign-on

Sat, 01 Aug 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Fri, 31 Jul 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 31 Jul 2026 07:30:00 +0000

Type Values Removed Values Added
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.
Title Keycloak-services: keycloak-services: secure-client-uris policy bypass via localhost-prefixed domains
First Time appeared Redhat
Redhat build Keycloak
Redhat jboss Data Grid
Redhat jbosseapxp
Redhat red Hat Single Sign On
Weaknesses CWE-20
CPEs cpe:/a:redhat:build_keycloak:
cpe:/a:redhat:jboss_data_grid:8
cpe:/a:redhat:jbosseapxp
cpe:/a:redhat:red_hat_single_sign_on:7
Vendors & Products Redhat
Redhat build Keycloak
Redhat jboss Data Grid
Redhat jbosseapxp
Redhat red Hat Single Sign On
References
Metrics cvssV3_1

{'score': 4.2, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-07-31T14:56:13.354Z

Reserved: 2026-07-29T08:24:18.687Z

Link: CVE-2026-18211

cve-icon Vulnrichment

Updated: 2026-07-31T14:56:09.086Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-07-28T12:55:48Z

Links: CVE-2026-18211 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-03T10:00:12Z

Weaknesses