CVE-2022-39352 is an authorization bypass vulnerability affecting OpenFGA, a high-performance authorization and permission engine inspired by Google's Zanzibar model. The vulnerability exists in versions prior to 0.2.5 and arises when a tuple with a wildcard (*) is assigned to a tupleset relation, specifically on the right-hand side of a 'from' statement in the authorization model. This incorrect authorization (CWE-863) allows an attacker or unauthorized user to bypass intended access controls under certain conditions, potentially granting access to resources or operations that should be restricted. The issue is rooted in the way OpenFGA processes tuplesets with wildcards, leading to improper enforcement of authorization policies. The vulnerability was addressed in version 0.2.5, but the patch introduces a non-backward-compatible change, meaning that authorization models using wildcards on tupleset relations must be updated to function correctly with the new version. There are no known exploits in the wild at this time, and the vulnerability was publicly disclosed in November 2022. The lack of a CVSS score necessitates an independent severity assessment based on the impact and exploitability characteristics.

For European organizations leveraging OpenFGA versions prior to 0.2.5, this vulnerability poses a risk of unauthorized access to sensitive systems, data, or services controlled by the OpenFGA authorization engine. Since OpenFGA is used to enforce fine-grained permissions, an authorization bypass could lead to privilege escalation, data leakage, or unauthorized operations within enterprise applications. This risk is particularly significant for sectors with stringent data protection requirements such as finance, healthcare, and government, where unauthorized access could result in regulatory non-compliance (e.g., GDPR violations) and reputational damage. The impact on confidentiality and integrity is moderate to high depending on the deployment context, while availability impact is likely low. The vulnerability requires specific conditions (use of wildcard tuples in authorization models), so not all deployments are equally affected. However, organizations that have adopted OpenFGA for complex permission models with wildcards are at higher risk. The non-backward-compatible patch may complicate remediation, potentially delaying fixes and prolonging exposure.

1. Upgrade OpenFGA to version 0.2.5 or later immediately to apply the patch that fixes the authorization bypass. 2. Review and refactor authorization models that use wildcards on tupleset relations to ensure compatibility with the updated OpenFGA version. This may require redesigning permission schemas to avoid wildcard usage or implementing alternative logic that complies with the new version's requirements. 3. Conduct thorough testing of authorization policies post-upgrade to verify that access controls are correctly enforced and no unintended permissions are granted. 4. Implement monitoring and auditing of authorization decisions and access logs to detect any anomalous access patterns that could indicate exploitation attempts. 5. For organizations unable to upgrade immediately, consider implementing compensating controls such as additional application-layer authorization checks or network segmentation to limit exposure. 6. Educate development and security teams about the implications of wildcard usage in authorization models and the importance of adhering to updated best practices.