CVE-2020-15133

In faye-websocket before version 0.11.0, there is a lack of certification
validation in TLS handshakes. The Faye::WebSocket::Client class uses the
EM::Connection#start_tls method in EventMachine to implement the TLS
handshake whenever a wss: URL is used for the connection. This method
does not implement certificate verification by default, meaning that it
does not check that the server presents a valid and trusted TLS certificate
for the expected hostname. That means that any wss: connection made using
this library is vulnerable to a man-in-the-middle attack, since it does not
confirm the identity of the server it is connected to. For further
background information on this issue, please see the referenced GitHub
Advisory. Upgrading faye-websocket to v0.11.0 is recommended.

Bugs

• <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=967061&gt;