CVE-2026-16584 - AWS API MCP Server Security Policy Bypass via Startup Failure

Summary

CVE-2026-16584 affects the AWS API MCP Server (awslabs.aws-api-mcp-server) for versions >= 0.2.13 and < 1.3.47. If the server fails to load its optional user-configured security policy at startup, it keeps running with the per-request policy check skipped, so AWS API operations the policy was set to deny or gate can execute without enforcement, provided fail-closed modes are not enabled. IAM permissions on the configured credentials remain in effect.

Mitigation

The source does not state a fix yet. Check the original advisory for updates.

Topics

• Model Context Protocol

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