undici vulnerable to Denial of Service via unrequested WebSocket subprotocol
Impact
The undici WebSocket client throws an uncaught TypeError during the opening handshake when a server's 101 response includes a Sec-WebSocket-Protocol header that the client never requested. The throw occurs in a queueMicrotask callback with no surrounding try/catch, so it propagates as an uncaught exception and terminates the Node.js process. This is a remote, unauthenticated denial of service against any application that opens a WebSocket to an attacker controlled or compromised server, or over a plaintext ws:// connection subject to a machine-in-the-middle. It affects the default new WebSocket(url) usage, where no subprotocol is requested. Per RFC 6455 section 4.1, an unrequested subprotocol must fail the connection, not crash it.
All releases starting at undici 6.7.0 are affected.
Patches
Upgrade to undici 6.28.1, 7.29.1, or 8.10.2.
Workarounds
No workaround is available. The fix must be applied through an upgrade.
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Paquete de npm | undici | >= 6.7.0, < 6.28.1, >= 7.0.0, < 7.29.1, >= 8.0.0, < 8.10.2 | 6.28.1, 7.29.1, 8.10.2 |
Referencias
- https://github.com/nodejs/undici/security/advisories/GHSA-rfgv-xxqx-mfg5
- https://nvd.nist.gov/vuln/detail/CVE-2026-19534
- https://github.com/nodejs/undici/commit/2af0faf88b906d3127a360c3ac75164c0f95e5a5
- https://github.com/nodejs/undici/commit/6615e0175e9b635bcd2e3e87a47daa82f6f5b728
- https://github.com/nodejs/undici/commit/66e12816064cf3068f63bd134748b7fc4e779bad
- https://cna.openjsf.org/security-advisories.html
- https://github.com/nodejs/undici
- https://github.com/nodejs/undici/releases/tag/v6.28.1
- https://github.com/nodejs/undici/releases/tag/v7.29.1
- https://github.com/nodejs/undici/releases/tag/v8.10.2
- Vector CVSS
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Debilidad (CWE)
CWE-248, CWE-252- Plataforma
- npm
- Paquete
undici- Publicada
- 29.09.2026
- Actualizado
- 11.10.2026 10:22
Fuentes y licencias
OSV / GitHub Advisory Database - GHSA-rfgv-xxqx-mfg5 - CC BY 4.0
Historial de vulnerabilidades: undici
Todas las vulnerabilidades publicadas de este paquete (Paquete de npm), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.
- Entradas en total
- 46
- Primera → última
- 06.2022 09.2026
- Sin corrección
- 0
- Explotada en ataques
- 0
Distribución por gravedad
- Alta 13
- Media 21
- Baja 12
Divulgaciones por año
- 2022: 5
- 2023: 3
- 2024: 5
- 2025: 2
- 2026: 31
-
undici vulnerable to Denial of Service via unrequested WebSocket subprotocol esta entrada
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