Red Hat Keycloak TokenManager improper authentication

Summaryinfo

A vulnerability classified as critical has been found in Red Hat Keycloak. The affected element is an unknown function of the component TokenManager. Performing a manipulation results in improper authentication. This vulnerability is known as CVE-2026-96447. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in Red Hat Keycloak (version now known). It has been classified as critical. This affects some unknown processing of the component TokenManager. The manipulation with an unknown input leads to a improper authentication vulnerability. CWE is classifying the issue as CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

A flaw was found in the TokenManager component of Keycloak, an open-source identity and access management solution. The issue occurs during the validation of stateless access tokens when the original user ID no longer exists. Keycloak incorrectly falls back to using the username to identify the user without verifying if the identity matches the original token subject. This could allow an attacker with an old token to gain access to a newly created service account if it shares the same client ID as a previously deleted one.

The advisory is shared at access.redhat.com. This vulnerability is uniquely identified as CVE-2026-96447 since 09/23/2026. The exploitability is told to be easy. It is possible to initiate the attack 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 11/06/2026).

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

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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