CVE-2026-4270

Medium

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.

SeverityMedium

CVSS5.5

Exploit probability—

ProductAmazon Aws Api Mcp Server

PublishedMar 16, 2026

First seenMar 16, 2026

Weakness typeCWE-424CWE-424

How to fix

Update

amazon aws_api_mcp_server1.3.9 or later
awslabs-aws-api-mcp-server1.3.9 or later

Patches

pypi.org/project/awslabs.aws-api-mcp-server/1.3.9/

Vendor advisories

aws.amazon.com/security/security-bulletins/2026-007-AWS/

Affected products

Product	Affected versions	Fixed in
amazon aws_api_mcp_server	0.2.14 ≤ v < 1.3.9	1.3.9
awslabs-aws-api-mcp-serverPyPI	0.2.14 ≤ v < 1.3.9	1.3.9

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.