Red Hat Keycloak/Single Sign-On Client Management improper authorization

Summaryinfo

A vulnerability has been found in Red Hat Keycloak and Single Sign-On and classified as very critical. This impacts an unknown function of the component Client Management. The manipulation leads to improper authorization. This vulnerability is uniquely identified as CVE-2026-120984. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Red Hat Keycloak and Single Sign-On (the affected version unknown) and classified as very critical. This issue affects an unknown part of the component Client Management. 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:

A flaw was found in the Keycloak server's client management component. When a client is created or imported with authorization services enabled, the system fails to properly clear an internal session attribute used during the setup process. This allows an authenticated attacker with client management permissions to bypass security controls and upload a malicious JavaScript policy, which is then executed on the server when an authorization request is made. Successful exploitation could allow the attacker to run arbitrary code on the server, potentially compromising the entire system.

The advisory is shared at access.redhat.com. The identification of this vulnerability is CVE-2026-120984 since 11/03/2026. The exploitation is known to be easy. The attack may be initiated remotely. Additional levels of successful authentication are required for exploitation. 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 11/07/2026). 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.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• Red Hat

Name

• Keycloak
• Single Sign-On

License

• open-source

Website

• Vendor: https://www.redhat.com/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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