CVE-2026-16584
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Security Policy Bypass in AWS API MCP Server

Publication date: 2026-07-23

Last updated on: 2026-07-23

Assigner: AMZN

Description
Improper handling of an initialization failure in AWS API MCP Server from 0.2.13 through 1.3.46 might allow an actor to bypass the user-configured security policy and execute AWS API operations that the policy was set to deny or gate. When initialization of the security policy enforcement data fails at server startup, the policy check is skipped for the lifetime of the process. IAM permissions on the configured credentials remain in effect and are unaffected. To remediate this issue, users should upgrade to version 1.3.47.

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Meta Information

Published
2026-07-23
Last Modified
2026-07-23
Generated
2026-07-23
AI Q&A
2026-07-23
EPSS Evaluated
N/A
NVD
CVE-2026-16584
EUVD
EUVD-2026-48299

Affected Vendors & Products

Showing 5 associated CPEs
Vendor Product Version / Range
awslabs aws-api-mcp-server From 0.2.13 (inc) to 1.3.47 (exc)
awslabs aws-api-mcp-server From 1.3.46 (inc) to 1.3.47 (exc)
awslabs aws-api-mcp-server 1.3.47
aws api_mcp_server From 0.2.13 (inc) to 1.3.46 (inc)
aws api_mcp_server 1.3.47

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-455 The product does not exit or otherwise modify its operation when security-relevant errors occur during initialization, such as when a configuration file has a format error or a hardware security module (HSM) cannot be activated, which can cause the product to execute in a less secure fashion than intended by the administrator.

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Executive Summary

This vulnerability involves improper handling of initialization failure in the AWS API MCP Server. When the server fails to load security policy data during startup, it skips policy checks permanently, allowing restricted AWS operations to bypass configured restrictions. The issue affects versions 0.2.13 through 1.3.46.

Detection Guidance

To detect this vulnerability, check the version of the AWS API MCP Server running on your system. If it is between 0.2.13 and 1.3.46, it is vulnerable. Use the command: pip show awslabs.aws-api-mcp-server to check the installed version.

Impact Analysis

An attacker could exploit this to execute AWS operations that the security policy was meant to block. While IAM permissions remain unaffected, unauthorized actions may occur if the policy was configured to deny them. This could lead to data breaches, unauthorized resource access, or other security incidents.

Compliance Impact

This vulnerability could lead to unauthorized access or data exposure, violating compliance requirements for GDPR, HIPAA, or other regulations that mandate strict access controls and audit logging. Bypassing security policies may result in non-compliance with data protection standards.

Mitigation Strategies

Immediately upgrade the AWS API MCP Server to version 1.3.47 or later using pip install --upgrade awslabs.aws-api-mcp-server. Alternatively, use least-privilege IAM credentials and ensure the server restarts after connectivity issues.

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