CVE-2026-61666 — websocket-driver: Denial of service via malformed Host header

Affected: faye websocket-driver-ruby

websocket-driver is a WebSocket protocol handler with pluggable I/O. Prior to 0.8.2, WebSocket::Driver.server() passes a malformed Host header to URI.parse in lib/websocket/http/request.rb without catching URI::InvalidURIError, allowing a remote client to crash a TCP-backed WebSocket server when the application does not catch the error from parse(). This issue is fixed in version 0.8.2.

GHSA-2x63-gw47-w4mm — websocket-driver-ruby: Denial of service via malformed Host header

Affected: RubyGems: websocket-driver

### 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.

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CVE-2026-61666 — websocket-driver: Denial of service via malformed Host header

GHSA-2x63-gw47-w4mm — websocket-driver-ruby: Denial of service via malformed Host header