CVE-2026-4269
Improper S3 ownership verification in Bedrock AgentCore Starter Toolkit
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.
INFO
Published Date :
March 16, 2026, 6:16 p.m.
Last Modified :
March 16, 2026, 6:16 p.m.
Remotely Exploit :
Yes !
Source :
ff89ba41-3aa1-4d27-914a-91399e9639e5
Affected Products
The following products are affected by CVE-2026-4269
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | ff89ba41-3aa1-4d27-914a-91399e9639e5 | ||||
| CVSS 4.0 | MEDIUM | ff89ba41-3aa1-4d27-914a-91399e9639e5 | ||||
| CVSS 4.0 | MEDIUM | ff89ba41-3aa1-4d27-914a-91399e9639e5 |
Solution
- Upgrade Bedrock AgentCore Starter Toolkit to v0.1.13.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-4269.
| URL | Resource |
|---|---|
| https://aws.amazon.com/security/security-bulletins/2026-008-AWS/ | |
| https://github.com/aws/bedrock-agentcore-starter-toolkit/releases/tag/v0.1.13 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-4269 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-4269
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-4269 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-4269 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by ff89ba41-3aa1-4d27-914a-91399e9639e5
Mar. 16, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:N/AC:H/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H Added CWE CWE-283 Added CWE CWE-340 Added Reference https://aws.amazon.com/security/security-bulletins/2026-008-AWS/ Added Reference https://github.com/aws/bedrock-agentcore-starter-toolkit/releases/tag/v0.1.13