Vulnerability · Published Aug 17, 2026 · Assigned by GitHub_M
CVE-2026-61666websocket-driver: Denial of service via malformed Host header
High 8.9
In plain English
A high-severity security flaw in websocket-driver-ruby from faye. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | ruby-websocket-driver | no fix listed | DEBIAN-CVE-2026-61666 |
| Debian:13 | ruby-websocket-driver | no fix listed | DEBIAN-CVE-2026-61666 |
| Debian:14 | ruby-websocket-driver | 0.8.2-1 | DEBIAN-CVE-2026-61666 |
| RubyGems | websocket-driver | 0.8.2 | GHSA-2x63-gw47-w4mm |
| Ubuntu:22.04:LTS | ruby-websocket-driver | no fix listed | UBUNTU-CVE-2026-61666 |
| Ubuntu:24.04:LTS | ruby-websocket-driver | no fix listed | UBUNTU-CVE-2026-61666 |
| Ubuntu:26.04:LTS | ruby-websocket-driver | no fix listed | UBUNTU-CVE-2026-61666 |
| Ubuntu:26.10 | ruby-websocket-driver | no fix listed | UBUNTU-CVE-2026-61666 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| faye | websocket-driver-ruby | < 0.8.2 |
Weakness: CWE-248 · 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