Red Hat Keycloak Token Exchange improper authorization

Summaryinfo

A vulnerability identified as critical has been detected in Red Hat Keycloak. This issue affects some unknown processing of the component Token Exchange. The manipulation leads to improper authorization. This vulnerability is uniquely identified as CVE-2026-18215. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Red Hat Keycloak (affected version not known). It has been rated as critical. This issue affects some unknown functionality of the component Token Exchange. The manipulation with an unknown input leads to a improper authorization vulnerability. Using CWE to declare the problem leads to CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Keycloak provides a way to let users log in using Microsoft accounts while restricting access to a specific organization (tenant). A flaw was discovered where this restriction is ignored when using the token exchange feature. This means an attacker with a valid Microsoft token from a completely different organization could gain access to the Keycloak realm, potentially accessing sensitive data or performing unauthorized actions.

The advisory is shared at access.redhat.com. The identification of this vulnerability is CVE-2026-18215 since 07/29/2026. The exploitation is known to be easy. The attack may be initiated remotely. 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 T1548.002 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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