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TI-2026-84122 Aliases CVE-2026-116635

Path traversal in AWS Serverless MCP Server lets agents read and write files

Priority LOW 30CWE-23Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
High · Low · None
Fix status
Fixed

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

Summary

The AWS Serverless MCP Server (aws-serverless-mcp-server) before v0.2.1 has an improper limitation of a pathname to a restricted directory in its deployment status component (CWE-23). An actor who can influence the MCP agent can read JSON files outside the intended deployment status directory, and where write access is enabled, create or overwrite JSON files outside that directory. The flaw is reachable through directory traversal sequences or an absolute path supplied in the project name input.

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

Description from the CNA

Improper limitation of a pathname to a restricted directory in the deployment status component of the AWS Serverless MCP Server (aws-serverless-mcp-server) before v0.2.1 might allow an actor who can influence the MCP agent to read the contents of JSON files outside the intended deployment status directory. Where write access has been enabled, to create or overwrite JSON files outside that directory. This issue is reachable through directory traversal sequences or an absolute path supplied in the project name input. To remediate this issue, users should upgrade to version v0.2.1.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00313 24th percentileScored 2026-11-07
Fix Fixed aws-serverless-mcp-server (AWS): 0.2.1

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-serverless-mcp-serverbefore 0.2.10.2.1Patch availableCNA
  • aws-serverless-mcp-server VendorAWS Affected before 0.2.1 Fixed in 0.2.1 Patch available CNA

Remediation

Upgrade aws-serverless-mcp-server to version 0.2.1.

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

  • Fix · CNA aws-serverless-mcp-server (AWS) Fixed in 0.2.1

Timeline

  1. 2026-11-02 Threatist record created from CVE-2026-116635
  2. 2026-11-04 Priority changed: MEDIUM → LOW
  3. 2026-11-06 CISA SSVC decision points changed

References

Patch 1

Advisory 2

  • 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

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences