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

Summary

CVE-2026-18953 is an improper limitation of a pathname to a restricted directory in the get_resource tool of awslabs.aws-transform-mcp-server, a locally run MCP server, in versions 0.1.0 through 0.1.4. A context-dependent actor can use the savePath parameter to write arbitrary files outside the intended working directory, which could lead to local code execution.

Mitigation

Fixed in 0.1.5 (the source states the flaw is present before 0.1.5).

Topics

• Model Context Protocol

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