Vulnerabilities in pkg:pypi/bedrock-agentcore-starter-toolkit

PACKAGE
Advisory Identifier: GHSA-xfhr-q72q-jcrj
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Advisory Summary

CVE-2026-4269 is a MODERATE (CVSS 7.5) improper s3 ownership verification vulnerability (CWE-283: Unverified Ownership) affecting Bedrock agentcore starter toolkit libraries in the PyPI ecosystem. The issue involves improper s3 ownership verification in bedrock agentcore starter toolkit. Remediation is available by upgrading affected packages to version 0.1.13.

1 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:pypi/bedrock-agentcore-starter-toolkit

1 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:pypi/bedrock-agentcore-starter-toolkit. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-xfhr-q72q-jcrj CVE-2026-4269 MODERATE Improper S3 ownership verification in Bedrock AgentCore Starter Toolkit

CVE-2026-4269 at a Glance

CVE Identifier CVE-2026-4269
GHSA Identifier GHSA-xfhr-q72q-jcrj
Severity MODERATE
CVSS v3.1 Base Score 7.5
CWE Classification CWE-283: Unverified Ownership
Affected Product Bedrock agentcore starter toolkit
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-4269

To remediate this vulnerability, upgrade all affected Bedrock agentcore starter toolkit dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

bedrock-agentcore-starter-toolkit fixed: 0.1.13 
pip install bedrock-agentcore-starter-toolkit>=0.1.13
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show bedrock-agentcore-starter-toolkit

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-4269, inspect your installed packages using pip:

pip show bedrock-agentcore-starter-toolkit

Analyze the terminal output to locate any version of Bedrock agentcore starter toolkit in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.1.13), your application is affected.

Note: The pip show bedrock-agentcore-starter-toolkit command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-283: Unverified Ownership, where the product does not properly verify that a critical resource is owned by the proper entity. In Bedrock agentcore starter toolkit, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## Summary An issue has been identified in the Bedrock AgentCore Starter Toolkit versions prior to v0.1.13 that may allow a remote actor to inject code during the build process, leading to code execution in the AgentCore Runtime. ## Impact A remote actor could inject code during the build process, leading to code execution in the AgentCore Runtime and a complete loss of confidentiality, integrity, and availability of the affected AgentCore resource. 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 date are not affected. ## Patches This issue has been addressed in version v0.1.13. AWS recommends upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes. ## Workarounds N/A ## References If you have any questions or comments about this advisory, contact [AWS/Amazon] Security via our [vulnerability reporting page](https://aws.amazon.com/security/vulnerability-reporting) or directly via email to [aws-security@amazon.com](mailto:aws-security@amazon.com). Please do not create a public GitHub issue.

CVE-2026-4269 Affected Bedrock agentcore starter toolkit Versions

1 component(s)
Fixed Versions:
0.1.13
Product / Package Ecosystem Affected Versions Fixed Version
bedrock-agentcore-starter-toolkit
pypi/bedrock-agentcore-starter-toolkit
PyPI
< 0.1.13
0.1.13

References

GitHub Advisory / Wiki ADVISORY
https://github.com/aws/bedrock-agentcore-starter-toolkit/security/advisories/GHSA-xfhr-q72q-jcrj
NVD — CVE-2026-4269 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-4269
Bedrock agentcore starter toolkit Security Information SECURITY
https://aws.amazon.com/security/security-bulletins/2026-008-AWS
Bedrock agentcore starter toolkit Source Repository REPOSITORY
https://github.com/aws/bedrock-agentcore-starter-toolkit
Bedrock agentcore starter toolkit Release RELEASE
https://github.com/aws/bedrock-agentcore-starter-toolkit/releases/tag/v0.1.13

Frequently Asked Questions

What is CVE-2026-4269?
CVE-2026-4269 is a security vulnerability in Bedrock agentcore starter toolkit involving Improper S3 ownership verification in Bedrock AgentCore Starter Toolkit under CWE-283: Unverified Ownership.
Which Bedrock agentcore starter toolkit versions are affected?
Affected versions include releases prior to 0.1.13 across affected packages: bedrock-agentcore-starter-toolkit.
What version fixes CVE-2026-4269?
Upgrading to 0.1.13 (or the latest patched release for your respective branch) resolves the vulnerability.
Is bedrock-agentcore-starter-toolkit affected?
Yes, bedrock-agentcore-starter-toolkit is affected in releases prior to 0.1.13. Upgrade your dependency to 0.1.13 or later.
What is the CVSS score of CVE-2026-4269?
CVE-2026-4269 has a CVSS v3.1 base score of 7.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-4269?
CVE-2026-4269 is classified under CWE-283: Unverified Ownership (The product does not properly verify that a critical resource is owned by the proper entity.).
How can I check PyPI dependencies for CVE-2026-4269?
Run the dependency tree command: 'pip show bedrock-agentcore-starter-toolkit'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-xfhr-q72q-jcrj",
  "modified" : "2026-03-17T20:34:21Z",
  "published" : "2026-03-17T20:34:21Z",
  "aliases" : [ "CVE-2026-4269" ],
  "summary" : "Improper S3 ownership verification in Bedrock AgentCore Starter Toolkit",
  "details" : "## Summary\nAn issue has been identified in the Bedrock AgentCore Starter Toolkit versions prior to v0.1.13 that may allow a remote actor to inject code during the build process, leading to code execution in the AgentCore Runtime.\n\n\n## Impact\nA remote actor could inject code during the build process, leading to code execution in the AgentCore Runtime and a complete loss of confidentiality, integrity, and availability of the affected AgentCore resource.\n\nImpacted 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 date are not affected. \n\n## Patches\nThis issue has been addressed in version v0.1.13. AWS recommends upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes. \n\n## Workarounds\nN/A\n\n## References\nIf you have any questions or comments about this advisory, contact [AWS/Amazon] Security via our [vulnerability reporting page](https://aws.amazon.com/security/vulnerability-reporting) or directly via email to [aws-security@amazon.com](mailto:aws-security@amazon.com). Please do not create a public GitHub issue.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "bedrock-agentcore-starter-toolkit"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.1.13"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/aws/bedrock-agentcore-starter-toolkit/security/advisories/GHSA-xfhr-q72q-jcrj"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-4269"
  }, {
    "type" : "WEB",
    "url" : "https://aws.amazon.com/security/security-bulletins/2026-008-AWS"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/aws/bedrock-agentcore-starter-toolkit"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/aws/bedrock-agentcore-starter-toolkit/releases/tag/v0.1.13"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-283", "CWE-340" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-17T20:34:21Z",
    "nvd_published_at" : "2026-03-16T18:16:11Z"
  }
}