CVE-2026-4270

Improper Protection of Alternate Path exists in the no-access and workdir feature of the AWS API MCP Server versions >= 0.2.14 and < 1.3.9 on all platforms may allow the bypass of intended file access restriction and expose arbitrary local file contents in the MCP client application context. To remediate this issue, users should upgrade to version 1.3.9.

CVSS v3 5.5 MEDIUM

5.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://aws.amazon.com/security/security-bulletins/2026-007-AWS/	Vendor Advisory
https://pypi.org/project/awslabs.aws-api-mcp-server/1.3.9/	Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:amazon:aws_api_mcp_server:*:*:*:*:*:python:*:*

History

21 May 2026, 15:58

Type	Values Removed	Values Added
Summary		(es) Protección Inadecuada de Ruta Alternativa existe en la característica no-access y workdir del servidor AWS API MCP versiones >= 0.2.14 y < 1.3.9 en todas las plataformas, lo que puede permitir la omisión de la restricción de acceso a archivos prevista y exponer contenidos de archivos locales arbitrarios en el contexto de la aplicación cliente MCP. Para remediar este problema, los usuarios deben actualizar a la versión 1.3.9.
First Time		Amazon Amazon aws Api Mcp Server
References	~~() https://aws.amazon.com/security/security-bulletins/2026-007-AWS/ -~~	() https://aws.amazon.com/security/security-bulletins/2026-007-AWS/ - Vendor Advisory
References	~~() https://pypi.org/project/awslabs.aws-api-mcp-server/1.3.9/ -~~	() https://pypi.org/project/awslabs.aws-api-mcp-server/1.3.9/ - Third Party Advisory
CPE		cpe:2.3:a:amazon:aws_api_mcp_server::::::python::*

16 Mar 2026, 17:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-03-16 17:16

Updated : 2026-05-21 15:58

NVD link : CVE-2026-4270

Mitre link : CVE-2026-4270

CVE.ORG link : CVE-2026-4270

JSON object : View

Products Affected

amazon

aws_api_mcp_server

CWE

CWE-424

Improper Protection of Alternate Path

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