CVE-2020-7663.yml

---
gem: websocket-extensions
cve: 2020-7663
ghsa: g6wq-qcwm-j5g2
url: https://github.com/faye/websocket-extensions-ruby/security/advisories/GHSA-g6wq-qcwm-j5g2
date: 2020-06-05
title: Regular Expression Denial of Service in websocket-extensions (RubyGem)
description: |
  ### Impact

  The ReDoS flaw allows an attacker to exhaust the server's capacity to process
  incoming requests by sending a WebSocket handshake request containing a header
  of the following form:

      Sec-WebSocket-Extensions: a; b="\c\c\c\c\c\c\c\c\c\c ...

  That is, a header containing an unclosed string parameter value whose content is
  a repeating two-byte sequence of a backslash and some other character. The
  parser takes exponential time to reject this header as invalid, and this will
  block the processing of any other work on the same thread. Thus if you are
  running a single-threaded server, such a request can render your service
  completely unavailable.

  ### Workarounds

  There are no known work-arounds other than disabling any public-facing WebSocket functionality you are operating.
cvss_v3: 7.5
patched_versions:
  - ">= 0.1.5"

related:
  url:
    - https://blog.jcoglan.com/2020/06/02/redos-vulnerability-in-websocket-extensions/