Red Hat Keycloak Client Configuration server-side request forgery

Summaryinfo

A vulnerability categorized as critical has been discovered in Red Hat Keycloak. This vulnerability affects unknown code of the component Client Configuration Handler. Such manipulation leads to server-side request forgery. This vulnerability is traded as CVE-2026-4366. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in Red Hat Keycloak (affected version unknown) and classified as critical. Affected by this issue is an unknown functionality of the component Client Configuration Handler. The manipulation with an unknown input leads to a server-side request forgery vulnerability. Using CWE to declare the problem leads to CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. Impacted is confidentiality, integrity, and availability. CVE summarizes:

A flaw was identified in Keycloak, an identity and access management solution, where it improperly follows HTTP redirects when processing certain client configuration requests. This behavior allows an attacker to trick the server into making unintended requests to internal or restricted resources. As a result, sensitive internal services such as cloud metadata endpoints could be accessed. This issue may lead to information disclosure and enable attackers to map internal network infrastructure.

The advisory is shared for download at access.redhat.com. This vulnerability is handled as CVE-2026-4366 since 03/18/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 03/22/2026).

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

The vulnerability is also documented in the databases at EUVD (EUVD-2026-12762) and CERT Bund (WID-SEC-2026-0768). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

• Open Source Keycloak

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Vendor

• Red Hat

Name

• Keycloak

License

• open-source

Website

• Vendor: https://www.redhat.com/

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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