Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to 41.10.6, 42.9.2, 43.4.1, and 44.0.0-beta.5, windows opened from a sandboxed top-level document did not inherit that document's active HTML sandbox restrictions. Untrusted content in a sandboxed top-level document that was permitted to open popups could therefore create a window with the Electron application's full origin instead of the restricted origin intended by the sandbox. Applications that deny such popups with setWindowOpenHandler are not affected. This issue is fixed in versions 41.10.6, 42.9.2, 43.4.1, and 44.0.0-beta.5.