CVE-2026-4269 - Improper S3 ownership verification in Bedrock AgentCore Starter Toolkit
Bulletin ID: 2026-008-AWS
Scope: AWS
Content Type: Important (requires attention)
Publication Date: 03/16/2026 11:15 AM PDT
Description:
A missing S3 ownership verification in the Bedrock AgentCore Starter Toolkit before version v0.1.13 may allow a remote actor to inject code during the build process, leading to code execution in the AgentCore Runtime.
Impacted versions: All versions of Bedrock AgentCore Starter Toolkit versions before v0.1.13. This issue only affects users of the Bedrock AgentCore Starter Toolkit before version v0.1.13 who build the Toolkit after September 24, 2025. Any users on a version >=v0.1.13, and any users on previous versions who built the toolkit before September 24, 2025 are not affected.
Resolution:
To remediate this issue, customers should upgrade to version v0.1.13 or greater.
References:
Please email aws-security@amazon.com with any security questions or concerns.