CVE-2026-4270

EUVD-2026-12474
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
5.5 MEDIUM
LOCAL
LOW
NONE
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 5%
Affected Products (NVD)
VendorProductVersion
amazonaws_api_mcp_server
0.2.14 ≤
𝑥
< 1.3.9
𝑥
= Vulnerable software versions
Common Weakness Enumeration
References
https://aws.amazon.com/security/security-bulletins/2026-007-AWS/
https://pypi.org/project/awslabs.aws-api-mcp-server/1.3.9/