An important security bulletin has been issued by AWS regarding the Amazon SageMaker Python SDK. A vulnerability, CVE-2026-112408, was identified in the default_bucket() function. This flaw allows a remote actor who creates a specific S3 bucket first to potentially gain code execution and IAM credentials within a SageMaker environment. Versions of the SDK impacted include V2 prior to 2.257.3 and V3 from 3.0.0 up to, but not including, 3.10.0.