🛡️ CVE-2026-61666 — websocket-driver

🟠 CVSS 8.0 — High ✅ No Known Exploit CWE-248 OSV
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

websocket-driver-ruby: Denial of service via malformed Host header

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. Rated impact: confidentiality none, integrity none, availability high.

Affected software

CVE-2026-61666 is recorded against 1 package.

  • websocket-driver (fixed in 0.8.2)

Timeline and source

Published on 21 July 2026 and last revised on 23 July 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

github.com (Web)
github.com (Web)
github.com (Package)

Details

Severity HIGH
CVSS Score 8.0
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
CWE CWE-248
Public Exploit ✅ No
Source OSV
Published 2026-07-21
Updated 2026-08-12
Modified 2026-07-23
Fix URL N/A

Affected Packages

Software From version Fixed in
websocket-driver — 0.8.2

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