CVE-2026-43678 — MEDIUM (5.3)

Vulnerability Description

An unauthenticated remote peer can crash any NIOWebSocket-based server (including Vapor and Hummingbird) with a single 11-byte frame sent after a completed WebSocket handshake, dropping all active connections until the process restarts. This vulnerability is addressed in swift-nio version 2.101.0.

CVSS Score

5.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

NONE

Integrity

NONE

Availability

LOW

Related Weaknesses (CWE)

CWE-770 CWE-20

References

https://github.com/apple/swift-nio/security/advisories/GHSA-qcc5-f287-vgmq

FAQ

What is CVE-2026-43678?

CVE-2026-43678 is a vulnerability with a CVSS score of 5.3 (MEDIUM). An unauthenticated remote peer can crash any NIOWebSocket-based server (including Vapor and Hummingbird) with a single 11-byte frame sent after a completed WebSocket handshake, dropping all active con...

How severe is CVE-2026-43678?

CVE-2026-43678 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-43678?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.