CVE-2026-61666
Received Received - Intake

WebSocket Server Crash via Malformed Host Header in websocket-driver

Publication date: 2026-08-17

Last updated on: 2026-08-17

Assigner: GitHub, Inc.

Description
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.

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Meta Information

Published
2026-08-17
Last Modified
2026-08-17
Generated
2026-08-17
AI Q&A
2026-08-17
EPSS Evaluated
N/A
NVD
CVE-2026-61666
EUVD
EUVD-2026-60264

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
faye websocket-driver to 0.8.2 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-248 An exception is thrown from a function, but it is not caught.

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Executive Summary

CVE-2026-61666 is a denial-of-service vulnerability in the websocket-driver-ruby library versions before 0.8.2. It occurs when a WebSocket server uses WebSocket::Driver.server() on a TCP server. An attacker sends a malformed Host header, causing an uncaught URI::InvalidURIError that crashes the server if the application doesn't handle the error.

Detection Guidance

To detect this vulnerability, check if your system runs websocket-driver-ruby versions prior to 0.8.2. Use commands like 'gem list websocket-driver' or 'bundle list | grep websocket-driver' to verify the installed version.

Impact Analysis

This vulnerability allows remote attackers to crash your WebSocket server by sending a malformed Host header. If your application doesn't catch the error, the server process will terminate, causing downtime and disrupting services relying on WebSocket connections.

Compliance Impact

This vulnerability primarily impacts system availability by causing server crashes, which could lead to denial-of-service conditions. While it does not directly expose data, prolonged downtime may affect compliance with regulations like GDPR (data processing integrity) or HIPAA (service availability requirements) if critical systems are impacted.

Mitigation Strategies

Immediately update websocket-driver-ruby to version 0.8.2 or later. If updating is not possible, ensure your application catches URI::InvalidURIError exceptions when parsing Host headers to prevent server crashes.

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