CVE-2026-4270 | THREATINT

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.

PUBLISHED Reserved 2026-03-16 | Published 2026-03-16 | Updated 2026-03-16 | Assigner AMZN

MEDIUM: 5.5CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

MEDIUM: 6.8CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Problem types

CWE-424: Improper Protection of Alternate Path

Product status

Default status

unaffected

0.2.14 (custom) before 1.3.9

affected

References

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

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

cve.org (CVE-2026-4270)

nvd.nist.gov (CVE-2026-4270)

Download JSON