Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Amazon | Aws Api Mcp Server | >= 0.2.14, < 1.3.9 |
Related Weaknesses (CWE)
References
- 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
FAQ
What is CVE-2026-4270?
CVE-2026-4270 is a vulnerability with a CVSS score of 5.5 (MEDIUM). 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...
How severe is CVE-2026-4270?
CVE-2026-4270 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-4270?
Check the references section above for vendor advisories and patch information. Affected products include: Amazon Aws Api Mcp Server.