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.
Affected products
apple: swiftnio
References1
- github.com/apple/swift-nio/security/advisories/GHSA-qcc5-f287-v… Vendor Advisory
Metrics
- CVSS 3.1
-
5.3
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - EPSS — exploit probability
- 0% percentile: 32 · as of 10 November 2026
- CWE
- CWE-20CWE-770
Could this be exploited in your environment?
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