Vulnerability in Amazon bedrock-agentcore-starter-toolkit (CVE-2026-4269)
Summary
Vulnerability in Amazon bedrock-agentcore-starter-toolkit (CVE-2026-4269). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 0.1.13 or later.
Original description
The description as published by the source.
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.
Source: AWS Security Bulletins NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-4269 has been found in Amazon bedrock-agentcore-starter-toolkit.
Successful exploitation can lead to full system takeover. CVSS score: 7.5/10.
What to do: upgrade Amazon bedrock-agentcore-starter-toolkit to 0.1.13 or later.
If unsure, ask your IT team or search "Amazon bedrock-agentcore-starter-toolkit CVE-2026-4269" on the vendor's site.
CVE-2026-4269 (Amazon bedrock-agentcore-starter-toolkit) — CWE-283 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated
Patched: 0.1.13 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-283) exists in Amazon bedrock-agentcore-starter-toolkit.
Check the vendor advisory for the affected versions of Amazon bedrock-agentcore-starter-toolkit.
Severity: High (CVSS 7.5/10). Successful exploitation can lead to full system takeover.
Update to 0.1.13.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'bedrock-agentcore-starter-toolkit' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'bedrock-agentcore-starter-toolkit' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
bedrock-agentcore-starter-toolkitを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade Amazon bedrock-agentcore-starter-toolkit to 0.1.13ステージング環境で 0.1.13 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory aws.amazon.com
- advisory nvd.nist.gov
- advisory github.com
- AWS aws.amazon.com
- package github.com
- patch github.com
- web github.com
- web aws.amazon.com