CVE-2022-39230 is a vulnerability identified in the awslabs project 'fhir-works-on-aws-authz-smart,' specifically affecting versions 3.1.1 and 3.1.2. This project implements an authorization interface for FHIR Works, which is a framework designed to facilitate the deployment of FHIR (Fast Healthcare Interoperability Resources) APIs on AWS. The vulnerability is classified under CWE-200, indicating an exposure of sensitive information to unauthorized actors. The core issue arises during 'search-type' API requests, where a client can retrieve more information than their OAuth scope permits. However, the vulnerability does not allow access to data about individuals outside the client's authorized scope, limiting the exposure to data within the authorized patient set but potentially more than intended. Versions 3.1.0 and below are unaffected, and the issue is resolved in version 3.1.3 and later. No workaround exists, making upgrading imperative. The vulnerability does not appear to have been exploited in the wild so far. The flaw impacts confidentiality by exposing more sensitive data than authorized, but it does not affect integrity or availability. Exploitation requires the client to be authenticated and authorized to access some patient data, but the flaw allows escalation within that scope. The vulnerability is medium severity, reflecting the partial exposure and the requirement for prior authorization.

For European organizations, particularly those in healthcare or managing health data, this vulnerability poses a risk of unauthorized data exposure within the bounds of authorized patient records. Given the sensitive nature of healthcare data protected under GDPR and other privacy regulations, even limited overexposure can lead to compliance violations, reputational damage, and potential legal consequences. Organizations using fhir-works-on-aws-authz-smart versions 3.1.1 or 3.1.2 risk leaking more patient information than intended to authorized clients, which could be exploited by insiders or compromised clients to access excessive data. This could undermine patient trust and complicate regulatory audits. The impact is heightened in environments where fine-grained access control is critical and where multiple clients with varying scopes access the same FHIR API. Although the vulnerability does not allow access to unauthorized patient records, the overexposure within authorized records can still reveal sensitive health details beyond the minimum necessary, increasing privacy risks.

The primary and only effective mitigation is to upgrade fhir-works-on-aws-authz-smart to version 3.1.3 or later immediately. Since no workaround exists, organizations must prioritize patching to prevent data overexposure. Additionally, organizations should audit OAuth scopes and client permissions to ensure they follow the principle of least privilege, minimizing the potential data accessible even if overexposure occurs. Implementing enhanced monitoring and logging of API requests can help detect unusual access patterns or excessive data retrieval. Conducting regular security reviews of authorization logic and testing with scoped clients can identify potential overexposure issues proactively. For organizations unable to upgrade immediately, restricting access to the affected API endpoints through network controls or API gateways with additional authorization checks may reduce risk temporarily, though this is not a full solution. Finally, organizations should review their incident response plans to handle potential data exposure events in compliance with GDPR notification requirements.