CVE-2026-115845

Incomplete validation in the run_script Python sandbox in AWS MCP Server

State: Published
Severity: 5.3 Medium
Published: Oct 23, 2026
Updated: Oct 23, 2026
Reserved: Oct 23, 2026

Description

An incomplete list of disallowed inputs in the Python code validator of the run_script tool in AWS MCP Server might allow an authenticated remote user to execute arbitrary code within their own isolated session environment via a crafted script.

AWS fixed this issue service-side. No customer action is required.

Scores

CVSS	Score	Vector	Source
4.0	5.3 Medium	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N	AMZN
3.1	6.4 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N	AMZN

Weaknesses

CWE-184 Incomplete list of disallowed inputs

Affected Products

Product	Versions
AWS MCP ServerAWS	N/AAffected

References

https://aws.amazon.com/security/security-bulletins/2026-149-aws/vendor-advisory

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