Cleartext storage of sensitive information in the @step and @remote decorator pipeline component in Amazon SageMaker Python SDK before v3.11.0 and v2.256.0 might allow an authenticated remote user to extract the HMAC signing key from SageMaker DescribePipeline API responses and forge valid integrity signatures for specially crafted function payloads, achieving code execution in another user's pipeline execution context within the same AWS account.

A cleartext storage vulnerability exists in the @step and @remote decorator pipeline components of the Amazon SageMaker Python SDK prior to versions v3.11.0 and v2.256.0. An authenticated remote user can extract an HMAC signing key from SageMaker DescribePipeline API responses due to the key being stored in plaintext. The exposed key allows an attacker to forge valid integrity signatures for specially crafted function payloads. This forgery enables code execution within another user's pipeline execution context inside the same AWS account. The vulnerability represents a significant lateral movement and privilege escalation risk within shared AWS environments. Fixes have been released in SageMaker Python SDK v2.256.0 and v3.11.0. AWS has published a security bulletin and GitHub advisory addressing the issue.