CVE-2026-4269
HIGHDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 15% of all known CVEs.
References
Related Vulnerabilities
Other CWE-283 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2020-8554 | Medium | 6.3 | 9.3% | - | Fix |
| CVE-2024-27903 | Critical | 9.8 | 8.9% | - | Fix |
| CVE-2021-24501 | High | 8.1 | 1.3% | - | Fix |
| CVE-2021-24500 | High | 8.1 | 0.6% | - | Fix |
| CVE-2025-1007 | Medium | 5.3 | 0.5% | - | Fix |
| CVE-2022-29220 | Medium | 6.5 | 0.5% | - | Fix |
Common questions
How do I fix CVE-2026-4269?
Upgrade bedrock agentcore starter toolkit to 0.1.13 or later.
Is CVE-2026-4269 being actively exploited?
Not that we know of. CVE-2026-4269 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.24% is the estimated probability that it will be exploited in the next 30 days. That is higher than 15% of all scored CVEs.
How severe is CVE-2026-4269?
CVE-2026-4269 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-4269 affect?
Published advisories record a fix for bedrock agentcore starter toolkit (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-11.