# CVE-2026-4269: Improper S3 ownership verification in Bedrock AgentCore Starter Toolkit

> CVE-2026-4269: Improper S3 ownership verification in Bedrock AgentCore Starter Toolkit. CVSS 7.5 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-4269
Last updated: 2026-06-17T10:56:19Z

- Published: 2026-03-16 18:03 UTC · Updated: 2026-06-17 10:56 UTC · Assigner: AMZN
- CVSS: 7.5 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
- EPSS: 0.25%, 16th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-283, CWE-340

## 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.

## Affected vendors and products

- AWS: Bedrock AgentCore Starter Toolkit

## Tracked companies

- [Amazon Web Services](https://rewindex.com/company/aws.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-4269)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-4269)
- [https://aws.amazon.com/security/security-bulletins/2026-008-AWS/](https://aws.amazon.com/security/security-bulletins/2026-008-AWS/)
- [https://github.com/aws/bedrock-agentcore-starter-toolkit/releases/tag/v0.1.13](https://github.com/aws/bedrock-agentcore-starter-toolkit/releases/tag/v0.1.13)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-4269 · Markdown: https://rewindex.com/cve/CVE-2026-4269.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-4269 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:50:55.370Z