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Incomplete input validation in AWS MCP Server run_script tool

Priority LOW 24CWE-184Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
Low · Low · None
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

AWS MCP Server's run_script tool checks Python code against an incomplete list of disallowed inputs (CWE-184). An authenticated remote user with low privileges can run arbitrary code within their own isolated session by submitting a crafted script.

Written with Claude Haiku 5.5 from the sources below · 2026-11-02

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00306 23rd percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
AWSAWS MCP ServerN/A—No fix listedCNA
  • AWS MCP Server VendorAWS Affected N/A Fixed in — No fix listed CNA

Remediation

The sources list no fixed version for AWS MCP Server. AWS fixed this issue service-side, and no customer action is required.

Written with Claude Haiku 5.5 from the sources below · 2026-11-02

Timeline

  1. 2026-10-23 Threatist record created from CVE-2026-115845
  2. 2026-10-23 Alias added: GHSA-jmwp-36mq-x645
  3. 2026-11-02 CISA SSVC decision points changed

References

  • TI-2026-23989 crypto: algif_aead - Revert to operating out-of-place KEVCVSS 3.1HIGH 7.8
  • TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
  • TI-2024-18648 Amazon AWS Amplify CLI before 12.10.1 incorrectly configures the role trust policy of IAM… CVSS 3.1CRITICAL 9.8
  • TI-2024-05929 Openssh: regresshion - race condition in ssh allows rce/dos CVSS 3.1HIGH 8.1
  • TI-2025-03847 Input validation issue in AWS Amplify Studio UI component properties CVSS 4.0CRITICAL 9.0
  • TI-2026-11603 HTTP/2 Stream Parser Confusion Body-Inspection Bypass in Amazon CloudFront with AWS WAF CVSS 4.0HIGH 7.9
See all 383 →

Sources