Researchers from Ruhr-Universität Bochum and the Niederrhein University of Applied Sciences discovered a set of attacks against all modern web browsers, such as Google Chrome, Microsoft Edge, Safari, and Mozilla Firefox. The attacks are a part of a category called cross-site leaks (XS-Leaks), an attack vector that allows one website to view the private contents of another tab. For example, a malicious website may use one of these techniques to read the emails of a user who is currently using their webmail. The researchers were attempting to map out all possible vulnerabilities in this category for further analysis, finding a total of thirty-four (34) XS-Leaks, fourteen (14) of which are completely new. While the category of attacks has seen real world use since 2007, the newest attacks have not yet been used in the wild. To completely eliminate these attack vectors, browser developers must harden their software against the new attacks. Users are urged to update their browsers when these issues are resolved. The researchers also created a website that allows users to test their browsers against these techniques to determine what they are vulnerable to.