CVE-2026-18953

Local code execution via unconstrained savePath write

Published Aug 5, 2026 · Updated Aug 5, 2026

Path traversal in AWS Transform MCP Server 0.1.0 through 0.1.4 allows context-dependent attackers to write arbitrary local files. The get_resource tool accepts the savePath parameter for downloaded artifacts without confining the resolved destination to its working directory. Successful use requires interaction through the locally spawned stdio server; writing to a code-loaded path grants execution in the affected user's context.

CVSS severity8.6
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in AWS Transform MCP Server 0.1.0 through 0.1.4 allows context-dependent attackers to write arbitrary local files. The get_resource tool accepts the savePath parameter for downloaded artifacts without confining the resolved destination to its working directory. Successful use requires interaction through the locally spawned stdio server; writing to a code-loaded path grants execution in the affected user's context.

The record

CVE
CVE-2026-18953
Published
Aug 5, 2026
Updated
Aug 5, 2026
Vendor
Amazon Web Services
Product
AWS Transform MCP Server
Classifications
CWE-22, CAPEC-126, T1204
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.1.0 <=0.1.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Amazon Web Services · AWS Transform MCP Serverversion=0.1.0 <=0.1.4

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
8.6Amazon Web ServicesCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
6.3Amazon Web ServicesCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CAPEC-126Path Traversal
T1204User Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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