### [CVE-2020-7663](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-7663)
![](https://img.shields.io/static/v1?label=Product&message=websocket-extensions%20(ruby)&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=n%2Fa&color=blue)
![](https://img.shields.io/static/v1?label=Vulnerability&message=Regular%20Expression%20Denial%20of%20Service%20(ReDoS)&color=brighgreen)

### Description

websocket-extensions ruby module prior to 0.1.5 allows Denial of Service (DoS) via Regex Backtracking. The extension parser may take quadratic time when parsing a header containing an unclosed string parameter value whose content is a repeating two-byte sequence of a backslash and some other character. This could be abused by an attacker to conduct Regex Denial Of Service (ReDoS) on a single-threaded server by providing a malicious payload with the Sec-WebSocket-Extensions header.

### POC

#### Reference
- https://snyk.io/vuln/SNYK-RUBY-WEBSOCKETEXTENSIONS-570830

#### Github
- https://github.com/ARPSyndicate/cvemon
- https://github.com/Live-Hack-CVE/CVE-2020-7663
- https://github.com/PalindromeLabs/awesome-websocket-security
- https://github.com/upsideon/shoveler