GitHub Advisoryadvisory · RubyGems
GHSA-2x63-gw47-w4mm websocket-driver-ruby: Denial of service via malformed Host header
HIGH
Official page ↗
- Aliases
- CVE-2026-61666
- Ecosystem
- RubyGems
- Packages
- websocket-driver
- Severity
- High
- CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
- Weaknesses
- CWE-248
- Reviewed
- 2026-07-21
Affected packages
• RubyGems websocket-driver: < 0.8.2 → fixed in 0.8.2
Description
Impact
If this library is used to implement a WebSocket server on top of a TCP server, by using the `WebSocket::Driver.server()` method, then a client can cause the server to crash by sending a `Host` header that is not a valid `host[:port]` string. When this happens, a `URI::InvalidURIError` exception is raised which is not caught, and this can cause the server process to crash if the application does not catch the error from the `parse()` method itself.
Patches
The issue has been patched in version 0.8.2 by making the request parser catch `URI::InvalidURIError` and enter an error state if the `Host` header is malformed. This means the request is considered invalid and should not establish a WebSocket connection.
Workarounds
No known workarounds exist.
Acknowledgements
This issue was discovered and reported by Pranjali Thakur, DepthFirst Security Research Team.
Related
Alias · CVE (1)
- CVE-2026-61666 websocket-driver is a WebSocket protocol handler with pluggable I/O. vulnerability
Weakness · CWE (1)
- CWE-248 Uncaught Exception weakness
References
- https://github.com/faye/websocket-driver-ruby/security/advisories/GHSA-2x63-gw47-w4mm web
- https://nvd.nist.gov/vuln/detail/CVE-2026-61666 advisory
- https://github.com/faye/websocket-driver-ruby/commit/7d6fd87759a2fdc83590d3b49ffa661dc53fa128 web
- https://github.com/faye/websocket-driver-ruby package
- https://github.com/rubysec/ruby-advisory-db/blob/a58f1d0a3343e85cef597970f2c5458dcfbaf909/gems/websocket-driver/CVE-2026-61666.yml web