id: PYSEC-2026-162
published: "2026-03-16T17:16:32.270Z"
modified: "2026-05-22T17:23:49.899310Z"
aliases:
- CVE-2026-4270
- GHSA-2cpp-j2fc-qhp7
details: |-
  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:
- package:
    name: awslabs-aws-api-mcp-server
    ecosystem: PyPI
    purl: pkg:pypi/awslabs-aws-api-mcp-server
  ranges:
  - type: ECOSYSTEM
    events:
    - introduced: 0.2.14
    - fixed: 1.3.9
  versions:
  - 0.2.14
  - 0.3.0
  - 0.3.1
  - 0.3.2
  - 0.3.3
  - 0.3.4
  - 1.0.0
  - 1.0.1
  - 1.0.2
  - 1.1.0
  - 1.1.1
  - 1.1.2
  - 1.1.3
  - 1.1.4
  - 1.1.5
  - 1.1.6
  - 1.1.7
  - 1.1.8
  - 1.2.0
  - 1.2.1
  - 1.2.2
  - 1.2.3
  - 1.3.0
  - 1.3.1
  - 1.3.2
  - 1.3.3
  - 1.3.4
  - 1.3.5
  - 1.3.6
  - 1.3.7
  - 1.3.8
  ecosystem_specific: {}
references:
- type: ADVISORY
  url: https://aws.amazon.com/security/security-bulletins/2026-007-AWS/
- type: ADVISORY
  url: https://pypi.org/project/awslabs.aws-api-mcp-server/1.3.9/
- type: ADVISORY
  url: https://github.com/advisories/GHSA-2cpp-j2fc-qhp7
severity:
- type: CVSS_V4
  score: 
    CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X