Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. Prior to 41.10.4, 42.5.2, and 43.0.0, popups opened from a sandboxed iframe through Electron's OpenURLFromTab navigation path, including links using target="_blank" or a middle-click, did not receive the inherited HTML sandbox restrictions. An untrusted iframe using the allow-scripts allow-popups configuration could therefore open a popup with the embedding application's full origin, exposing that origin's cookies, storage, and same-origin scripting capabilities. Applications that do not embed untrusted content in sandboxed iframes are not affected. This issue is fixed in versions 41.10.4, 42.5.2, and 43.0.0.