EUVD-2026-63577Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Full process crash dropping all active connections until restart constitutes total availability loss, justifying A:H over the NVD-assigned A:L; all other metrics align with the confirmed description.
Primary rating from Vendor (apple).
CVSS VectorVendor: apple
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Lifecycle Timeline
3DescriptionCVE.org
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.
AnalysisAI
NIOWebSocket in swift-nio (all versions before 2.101.0) crashes the hosting process when any unauthenticated remote peer sends a single crafted 11-byte WebSocket frame following a completed handshake, terminating all active connections until the service restarts. Frameworks built on swift-nio - including Vapor and Hummingbird - inherit this exposure whenever they accept WebSocket connections. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires network connectivity to a service running NIOWebSocket (swift-nio <2.101.0) with an accessible WebSocket endpoint. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The NVD-assigned CVSS of 5.3 Medium (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L) understates operational severity by rating availability impact as Low, despite the description confirming a full process crash that drops all active connections until restart - a total loss of service availability. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upgrade swift-nio to version 2.101.0 or later, the vendor-released patch confirmed via Apple product-security advisory GHSA-qcc5-f287-vgmq. … Detailed patch versions, workarounds, and compensating controls in full report. |
Threat intelligence, references, and detailed analysis are available after sign-in.
NIOHTTP1 and projects using it for generating HTTP responses can be subject to a HTTP Response Injection attack. Rated h
Some HTTP/2 implementations are vulnerable to a flood of empty frames, potentially leading to a denial of service. Rated
Some HTTP/2 implementations are vulnerable to unconstrained interal data buffering, potentially leading to a denial of s
Some HTTP/2 implementations are vulnerable to a settings flood, potentially leading to a denial of service. Rated high s
Some HTTP/2 implementations are vulnerable to a reset flood, potentially leading to a denial of service. Rated high seve
Some HTTP/2 implementations are vulnerable to resource loops, potentially leading to a denial of service. Rated high sev
Some HTTP/2 implementations are vulnerable to ping floods, potentially leading to a denial of service. Rated high severi
Some HTTP/2 implementations are vulnerable to window size manipulation and stream prioritization manipulation, potential
Some HTTP/2 implementations are vulnerable to a header leak, potentially leading to a denial of service. Rated medium se
Same weakness CWE-20 – Improper Input Validation
View allSame technique Denial Of Service
View allShare
External POC / Exploit Code
Leaving vuln.today