Issue with Amazon SageMaker Python SDK - Model artifact integrity verification issues (CVE-2026-8596 & CVE-2026-8597)

Bulletin ID: 2026-031-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 05/14/2026 13:00 PM PDT Amazon SageMaker Python SDK is an open-source library for training and deploying machine learning models on Amazon SageMaker. The ModelBuilder component simplifies model deployment by automating model artifact preparation and SageMaker model creation. We identified two issues affecting the model artifact integrity verification mechanism in the ModelBuilder/Serve component: - CVE-2026-8596: We identified a cleartext storage of sensitive information issue in the ModelBuilder/Serve component. When building models using ModelBuilder, the SDK stored an HMAC signing key as a container environment variable (SAGEMAKER_SERVE_SECRET_KEY). This key was returned in plaintext by SageMaker describe APIs (DescribeModel, DescribeEndpointConfig, DescribeModelPackage). A remote authenticated actor with permissions to call these APIs and S3 write access to the model artifact path could extract the key, forge valid integrity signatures for specially crafted model artifacts, and achieve code execution in inference containers. - CVE-2026-8597: We identified a missing integrity v...