Missing S3 Ownership Verification in Bedrock AgentCore Toolkit <v0.1.13 Allows RCE
CVE-2026-4269 Published on March 16, 2026
Improper S3 ownership verification in Bedrock AgentCore Starter Toolkit
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. This issue only affects users of the Bedrock AgentCore Starter Toolkit before version v0.1.13 who build or have built 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.
To remediate this issue, customers should upgrade to version v0.1.13.
Vulnerability Analysis
CVE-2026-4269 can be exploited with network access, requires user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Weakness Types
Generation of Predictable Numbers or Identifiers
The product uses a scheme that generates numbers or identifiers that are more predictable than required.
Unverified Ownership
The software does not properly verify that a critical resource is owned by the proper entity.
Products Associated with CVE-2026-4269
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Affected Versions
AWS Bedrock AgentCore Starter Toolkit:- Version 0.1.0 and below 0.1.13 is affected.