GHSA-29w2-fq35-v728: AWS API MCP Server Security Policy Bypass via Startup Initialization Failure

Summary

The AWS API MCP Server, an open source Model Context Protocol server for running AWS CLI commands, skips its per-request security policy check for the lifetime of the process if the policy enforcement data fails to load at startup. Deny and gate rules are then not consulted, so restricted AWS API operations execute, though IAM permissions on the configured credentials still apply. Affected versions are >= 0.2.13 and < 1.3.47.

Mitigation

Fixed in awslabs.aws-api-mcp-server version 1.3.47. Until upgrading, use least-privilege IAM credentials (for example, a ReadOnlyAccess role) scoped to the task, or restart the server once connectivity is restored if it started during degraded connectivity.

Topics

• Model Context Protocol

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