CVE-2026-4270: Amazon Aws API Mcp Server

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• Amazon Aws API Mcp Server: from 0.2.14, before 1.3.9 (fixed in 1.3.9)

Published 2026-03-16. Last modified 2026-06-17.