"This release [torproject.org] features an important security update [torproject.org] to Tor Browser [torproject.org] for Linux users. On Linux systems with GVfs/GIO [wikipedia.org] support Firefox allows to bypass proxy settings as it ships a whitelist of supported protocols. Once an affected user navigates to a specially crafted URL the operating system may directly connect to the remote host, bypassing Tor Browser. Tails [boum.org] and Whonix [whonix.org] users, and users of our sandboxed Tor Browser are unaffected, though."