Bulletin ID: 2026-103-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 09/09/2026 09:30 AM PDT Description: We identified an issue in awslabs.mysql-mcp-server (an open-source, self-hosted Model Context Protocol server distributed via github.com/awslabs/mcp and PyPI). In affected versions, under certain conditions the read-only enforcement could be circumvented via SQL inline comments, allowing a statement to run that the read-only check was expected to block. The read-only mode provided by the server is a best-effort safeguard and is not a substitute for correctly scoped database permissions; the effective boundary is the permissions of the configured MySQL user. This issue does not affect the confidentiality or integrity of any AWS service. awslabs.mysql-mcp-server is a client-side, self-managed package; customers control installation and the privileges of the database credentials they configure. Impacted versions: awslabs.mysql-mcp-server <= 1.0.21 Please refer to the article below for the most up-to-date and complete information related to this AWS Security Bulletin.