Electron is a framework for writing cross-platform desktop applications using JavaScript, HTML and CSS. A vulnerability in versions prior to 11.5.0, 12.1.0, and 13.3.0 allows a sandboxed renderer to request a "thumbnail" image of an arbitrary file on the user's system. The thumbnail can potentially include significant parts of the original file, including textual data in many cases. Versions 15.0.0-alpha.10, 14.0.0, 13.3.0, 12.1.0, and 11.5.0 all contain a fix for the vulnerability. Two workarounds aside from upgrading are available. One may make the vulnerability significantly more difficult for an attacker to exploit by enabling contextIsolation in one's app. One may also disable the functionality of the createThumbnailFromPath API if one does not need it.

Electron before versions 11.0.0-beta.6, 10.1.2, 9.3.1 or 8.5.2 is vulnerable to a context isolation bypass. Apps using both contextIsolation and sandbox: true are affected. Apps using both contextIsolation and nodeIntegrationInSubFrames: true are affected. This is a context isolation bypass, meaning that code running in the main world context in the renderer can reach into the isolated Electron context and perform privileged actions.