CVE-2026-108096 in graphql-index-transformer
Summary
by MITRE • 10/09/2026
Improper authorization in the query resolvers generated by @aws-amplify/graphql-index-transformer in AWS Amplify API Category before 3.1.2 might allow an authenticated remote user to read records owned by other users of the same application via crafted queries.
This issue has been addressed in @aws-amplify/graphql-index-transformer 3.1.2 https://www.npmjs.com/package/@aws-amplify/graphql-index-transformer/v/3.1.2 (included in @aws-amplify/data-construct 1.17.4 https://www.npmjs.com/package/@aws-amplify/data-construct/v/1.17.4 and @aws-amplify/graphql-api-construct 1.21.4 https://www.npmjs.com/package/@aws-amplify/graphql-api-construct/v/1.21.4 ). We recommend upgrading to the latest version ensuring any forked or derivative code is patched to incorporate the new fixes and then redeploying their backend.
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Analysis
by VulDB Data Team • 10/09/2026
The vulnerability identified in versions of @aws-amplify/graphql-index-transformer prior to 3.1.2 represents a critical failure in access control mechanisms within AWS Amplify API Category applications. This flaw specifically affects query resolvers that are automatically generated by the index transformer, which is responsible for creating secondary indexes on GraphQL models to support efficient querying and sorting operations. The core technical issue stems from an improper authorization logic embedded within these auto-generated resolver templates. When a developer defines data models with specific indexing requirements in their Amplify schema, the underlying infrastructure generates Lambda-based resolvers or AppSync function code that handles query execution. In vulnerable versions of this transformer library, the generated code fails to adequately enforce ownership checks against secondary index queries. This means that while primary key lookups might correctly validate user identity and record ownership through standard authorization rules, the path taken when querying via a secondary index bypasses these critical security boundaries.
From an operational perspective, this flaw allows authenticated remote users to perform unauthorized data access attacks. An attacker who has valid credentials for the application can craft specific GraphQL queries that target fields used in secondary indexes rather than primary keys. By doing so, they can retrieve records belonging to other tenants or users within the same multi-tenant environment. This constitutes a direct violation of confidentiality and isolation principles essential for SaaS applications built on AWS Amplify. The impact is particularly severe because it affects data integrity across user boundaries, potentially exposing sensitive personal information, financial records, or proprietary business data that should remain strictly private to individual account holders. Since the vulnerability relies on crafted queries targeting specific index structures, it may not be immediately detectable through standard application testing unless security audits specifically examine secondary index query paths and their associated authorization middleware execution flow.
This type of flaw is formally categorized under CWE-269, which describes Improper Privilege Management or Authorization Bypass Through User Control. In the context of the MITRE ATT&CK framework for enterprise security, this vulnerability aligns with techniques related to T1078 Valid Accounts and potentially T1530 Data from Cloud Storage Object if the underlying data is accessed via object storage interfaces exposed through the API. The attack vector requires authentication, placing it in the initial access or persistence phase depending on how long the attacker maintains their foothold after exploiting this authorization bypass to exfiltrate bulk datasets for further analysis or social engineering attacks.
The resolution provided by AWS involves upgrading the aws-amplify/graphql-index-transformer package to version 3.1.2 or later, which is also included in dependent packages such as aws-amplify/data-construct version 1.17.4 and @aws-amplify/graphql-api-construct version 1.21.4. These updated versions contain corrected resolver generation logic that properly injects ownership checks into the query execution pipeline for secondary indexes, ensuring that every data retrieval operation validates the requesting user's identity against the record owner metadata before returning results. Organizations utilizing AWS Amplify must audit their dependency trees to ensure this specific transformer package is updated across all relevant services and environments. It is crucial to note that if any custom code has been forked or derived from the original resolver templates, simply updating the npm package may not be sufficient; developers must manually patch these derivative codes to incorporate the new security fixes before redeploying their backend infrastructure. Regular dependency auditing using tools like npm audit or Snyk can help identify such outdated packages in CI/CD pipelines to prevent deployment of vulnerable configurations.