CVE-2026-4269 json
Improper S3 ownership verification in Bedrock AgentCore Starter Toolkit
published 2026-03-16 7 mo ago modified 2026-07-13 3 mo ago also GHSA-xfhr-q72q-jcrj , PYSEC-2026-2396 , EUVD-2026-12490
- cvss
- 7.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 17%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- pypi bedrock-agentcore-starter-toolkit 0.1.13
- AWS Bedrock AgentCore Starter Toolkit 0.1.13
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 7 mo ago
Exploit prediction
0.26% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H |
| CNA | 4.0 | 5.8 | 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 |
| CNA | 4.0 | 5.8 | 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/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 |
| OSV | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | bedrock-agentcore-starter-toolkit | <0.1.13 |
0.1.13 |
Affected products
- AWS Bedrock AgentCore Starter Toolkit
Classification
References
-
github.com
/aws/bedrock-agentcore-starter-toolkit/releases/tag/v0.1.13
patch, web, release-notes
-
aws.amazon.com
/security/security-bulletins/2026-008-AWS/
vendor-advisory
-
github.com
/aws/bedrock-agentcore-starter-toolkit/security/advisories/GHSA-xfhr-q72q-jcrj
web
-
nvd.nist.gov
/vuln/detail/CVE-2026-4269
advisory
-
aws.amazon.com
/security/security-bulletins/2026-008-AWS
web
-
github.com
/aws/bedrock-agentcore-starter-toolkit
package
-
pypi.org
/project/bedrock-agentcore-starter-toolkit
package
-
github.com
/advisories/GHSA-xfhr-q72q-jcrj
advisory
Sources
- CVE List CVE-2026-4269
- GitHub Advisory GHSA-xfhr-q72q-jcrj
- NVD CVE-2026-4269
- OSV PYSEC-2026-2396
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.