cve/2020/CVE-2020-15133.md

### [CVE-2020-15133](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-15133)
![](https://img.shields.io/static/v1?label=Product&message=faye-websocket&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=n%2Fa&color=blue)
![](https://img.shields.io/static/v1?label=Vulnerability&message=CWE-295%3A%20Improper%20Certificate%20Validation&color=brighgreen)

### Description

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.

### POC

#### Reference
No PoCs from references.

#### Github
- https://github.com/PalindromeLabs/awesome-websocket-security