Maker.js is a 2D vector line drawing and shape modeling for CNC and laser cutters. In versions up to and including 0.19.1, the `makerjs.extendObject` function copies properties from source objects without proper validation, potentially exposing applications to security risks. The function lacks `hasOwnProperty()` checks and does not filter dangerous keys, allowing inherited properties and potentially malicious properties to be copied to target objects. A patch is available in commit 85e0f12bd868974b891601a141974f929dec36b8, which is expected to be part of version 0.19.2.