GitHub Advisoryadvisory · PyPI

GHSA-2cpp-j2fc-qhp7 AWS API MCP File Access Restriction Bypass

MEDIUM Published 2026-03-17 Modified 2026-06-08 Official page ↗
Aliases
CVE-2026-4270
Ecosystem
PyPI
Packages
awslabs.aws-api-mcp-server, awslabs-aws-api-mcp-server
Severity
Moderate
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Weaknesses
CWE-424
Reviewed
2026-03-17

Affected packages

• PyPI awslabs.aws-api-mcp-server: >= 0.2.14, < 1.3.9 → fixed in 1.3.9 • PyPI awslabs-aws-api-mcp-server: >= 0.2.14, < 1.3.9 → fixed in 1.3.9

Description

Description The AWS API MCP Server is an open source Model Context Protocol (MCP) server that enables AI assistants to interact with AWS services and resources through AWS CLI commands. It provides programmatic access to manage your AWS infrastructure while maintaining proper security controls. This server acts as a bridge between AI assistants and AWS services, allowing you to create, update, and manage AWS resources across all available services. The server includes a configurable file access feature that controls how AWS CLI commands interact with the local file system. By default, file operations are restricted to a designated working directory (workdir), but this can be configured to allow unrestricted file system access (unrestricted) or to block all local file path arguments entirely (no-access). Description: 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.

Related

Alias · CVE (1)

  • 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… vulnerability

Weakness · CWE (1)

  • CWE-424 Improper Protection of Alternate Path weakness

References