---
id: CVE-2026-18211
title: >-
  A flaw was found in the secure-client-uris client policy executor within
  Keycloak core services
summary: >-
  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 redi…
severity: medium
cvss: 4.2
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N'
cwe:
  - CWE-20
vendor: redhat
product: build_of_keycloak
affected:
  - build_of_keycloak
published: '2026-07-31'
updated: '2026-08-07'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-18211'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-18211'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2508306'
    label: secalert@redhat.com
tags:
  - nvd
epss: 0.00178
epssPercentile: 0.07592
ingestedAt: '2026-08-08T14:22:57.461Z'
---

## Overview

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

- `build_of_keycloak`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.