Researchers have developed a way to track a user across different browsers on the same machine by querying the installed applications on the device. Certain applications, when installed, will create custom URL schemes that the browser can use to launch a URL in a specific application. A website builds a profile of applications installed on a device by attempting to open their known URL handlers and checking if the browser launches a prompt. The vulnerability was disclosed by FingerprintJS’ Konstantin Darutkin, a researcher from one of the most well-known fingerprinting scripts.
Source: https://www.bleepingcomputer.com/news/security/cross-browser-tracking-vulnerability-tracks-you-via-installed-apps/