CVE-2026-18953 - Improper limitation of a pathname in AWS Transform MCP Server

unknownCVE-2026-18953

Bulletin ID: 2026-075-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 08/05/2026 12:30 PM PDT Description: The AWS Transform MCP Server (awslabs.aws-transform-mcp-server) is an open-source Model Context Protocol (MCP) server that runs locally on a developer's machine and lets AI-powered assistants interact with AWS Transform to run code-transformation jobs and retrieve their artifacts. We identified CVE-2026-18953. Improper limitation of a pathname to a restricted directory in the get_resource tool in awslabs.aws-transform-mcp-server before 0.1.5 might allow a context-dependent actor to write arbitrary files outside the intended working directory via the savePath parameter, which could lead to local code execution. Impacted versions: >=0.1.0 AND <=0.1.4 Please refer to the article below for the most up-to-date and complete information related to this AWS Security Bulletin.

CSIRTS triage

vendor: Amazon AWS product: AWS Transform MCP Server Path traversal Code injectionaffected: >=0.1.0 AND <=0.1.4

What: Improper pathname limitation in the get_resource tool allows writing arbitrary files outside the intended directory via savePath parameter.
Who is affected: Developers using AWS Transform MCP Server versions 0.1.0 through 0.1.4.
Urgency: High urgency; local code execution is possible through arbitrary file write capability.
Action: Update AWS Transform MCP Server to version 0.1.5 or later.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: AWS Security Bulletins (INTL · vendor-psirt · site)
Severity: unknown
Published: 2026-08-05
Exploitation: Not in CISA KEV at last sync

Original advisory: https://aws.amazon.com/security/security-bulletins/rss/2026-075-aws/

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-189530.15% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 5% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-18953	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

highCVE-2026-18953: Improper limitation of a pathname to a restricted directory in the get_resource tool in Amazon…nvd

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