Red Hat Keycloak/Single Sign-On User Session Note Mapper improper authorization

Summaryinfo

A vulnerability classified as problematic has been found in Red Hat Keycloak and Single Sign-On. Impacted is an unknown function of the component User Session Note Mapper. Performing a manipulation results in improper authorization. This vulnerability is reported as CVE-2026-105302. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Red Hat Keycloak and Single Sign-On (version now known). This affects some unknown processing of the component User Session Note Mapper. The manipulation with an unknown input leads to a improper authorization vulnerability. CWE is classifying the issue as 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. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

A flaw was found in the User Session Note mapper of the Keycloak identity and access management solution. The issue occurs because the mapper does not validate whether a requested session note contains sensitive internal credentials, such as federated access tokens from external identity providers. This allows a delegated client administrator to leak a user's upstream bearer tokens into the tokens issued to their managed application, potentially leading to unauthorized access to the user's data on external platforms.

The advisory is shared at access.redhat.com. This vulnerability is uniquely identified as CVE-2026-105302 since 10/05/2026. The exploitability is told to be easy. It is possible to initiate the attack 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 10/05/2026). 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.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-92257). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

• Red Hat

Name

• Keycloak
• Single Sign-On

License

• open-source

Website

• Vendor: https://www.redhat.com/

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Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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