Red Hat Keycloak Secure Client URIs Client Policy Executor redirect

Summaryinfo

A vulnerability has been found in Red Hat Keycloak and classified as problematic. Affected by this issue is some unknown functionality of the component Secure Client URIs Client Policy Executor. This manipulation causes redirect. This vulnerability is registered as CVE-2026-18211. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in Red Hat Keycloak (the affected version unknown). It has been declared as problematic. Affected by this vulnerability is an unknown part of the component Secure Client URIs Client Policy Executor. The manipulation with an unknown input leads to a redirect vulnerability. The CWE definition for the vulnerability is CWE-601. A web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a Redirect. This simplifies phishing attacks. As an impact it is known to affect integrity. The summary by CVE is:

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.

The advisory is shared at access.redhat.com. This vulnerability is known as CVE-2026-18211 since 07/29/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 07/31/2026). MITRE ATT&CK project uses the attack technique T1204.001 for this issue.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• Red Hat

Name

• Keycloak

License

• open-source

Website

• Vendor: https://www.redhat.com/

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