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CVE-2026-87912 and CVE-2026-87913: Missing S3 bucket ownership verification in the AWS Security Agent plugin for aws-agents-for-devsecops and MCP Server

Bulletin ID: 2026-105-AWS
Scope: AWS
Content Type: Important (requires attention)
Publication Date: 09/10/2026 08:30 AM PDT

Description:

AWS Security Agent is a managed AWS service that provides AI-powered code security reviews, threat modeling, and penetration testing.

We identified CVE-2026-87912, where a missing S3 bucket ownership verification in the AWS Security Agent plugin in Amazon aws-agents-for-devsecops before version 1.1.0 might allow remote attackers to obtain the private source archive of a scanned workspace, including credentials and infrastructure state contained in that archive, via a pre-registered storage bucket whose name is derived from a publicly known account identifier.

We identified CVE-2026-87913, where a missing S3 bucket ownership verification in the AWS Security Agent MCP server before 0.2.0 might allow remote attackers to obtain the private source archive of a scanned workspace, including credentials and infrastructure state contained in that archive, via a pre-registered storage bucket whose name is derived from a publicly known account identifier.

Impacted versions:

  • <=1.0.0
  • >=0.1.0 AND <=0.1.5

Resolution:

This issues has been addressed in agent-toolkit-for-aws and awslabs.security-agent-mcp-server version 0.2.0. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.

Workarounds:

Upgrading does not release a bucket name that a third party has already registered. We recommend that you verify the scan-input bucket security-agent-scans-<account-id>-<region> in your account is owned by your own account. As a precaution, you can pre-create that bucket in your own account before first use so that the predictable name cannot be registered by another account.

References:

Acknowledgement:

We would like to thank Nadav Claude Cohen from glow.io who reported this issue for collaborating with us through the coordinated vulnerability disclosure process.


Please email aws-security@amazon.com with any security questions or concerns.