# CVE-2026-115845: Incomplete validation in the run_script Python sandbox in AWS MCP Server

Status: published. Published: 2026-10-23. Updated: 2026-11-02.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- AWS / AWS MCP Server: Version not specified (affected, custom). Source: CNA: AMZN

## Severity and prioritization

- CVSS 3.1: 6.4 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N; source: CNA: AMZN

- CVSS 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; source: CNA: AMZN

- CISA KEV: No listing in collected sources

- EPSS: 0.31% as of 2026-11-01; percentile 23.41%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-184

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://aws.amazon.com/security/security-bulletins/2026-149-aws/ (CNA: AMZN; vendor-advisory)

## Provenance

- CNA: AMZN: https://www.cve.org/CVERecord?id=CVE-2026-115845; retrieved 2026-11-02; source updated 2026-11-02

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-115845; retrieved 2026-11-02; source updated Not reported

Revision: 3d65b99bbbee55eec96b5273d2168da5bd845b360e251d3e9746085cf4f708d6

Canonical: https://y2.dev/cve/CVE-2026-115845

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.