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 t…

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• cpe amazon/aws api mcp serverversion unspecified
• stated aws api mcp server< 1.3.9

How to fix CVE-2026-4270

• Recommended remediation

  Affected version ranges suggest a fixed boundary. Verify against the vendor advisory for your release.

• Official advisories

  • CVE.org · cve.org
  • FIRST EPSS · first.org
  • NIST NVD · nvd.nist.gov

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

1. Mar 16, 2026 · NIST NVD

   Detected

   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.

2. Jun 17, 2026 · NIST NVD

   Updated

   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.

Sources

• CVE.orgVulnerability recordCVE-2026-4270

  Official CVE identifier

  cve.org
• FIRST EPSSExploitation probabilityCVE-2026-4270

  30-day exploitation probability 0.2%

  first.org
• NIST NVDVulnerability recordCVE-2026-4270

  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 applicat

  nvd.nist.gov

References

• Vendor Advisory · aws.amazon.com
• Third Party Advisory · pypi.org

Freshness

Last verified in this catalog Oct 23, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.