CVE-2026-4269 | THREATINT

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. 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.

PUBLISHED Reserved 2026-03-16 | Published 2026-03-16 | Updated 2026-03-16 | Assigner AMZN

HIGH: 7.5CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

MEDIUM: 5.8CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H

Problem types

CWE-340 Generation of Predictable Numbers or Identifiers

CWE-283 Unverified Ownership

Product status

Default status

unaffected

0.1.0 (custom) before 0.1.13

affected

References

github.com/...agentcore-starter-toolkit/releases/tag/v0.1.13 patch

aws.amazon.com/security/security-bulletins/2026-008-AWS/ vendor-advisory

cve.org (CVE-2026-4269)

nvd.nist.gov (CVE-2026-4269)

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