En bref
- CVE-2026-19534 est une vulnérabilité ÉLEVÉE (CVSS 7.5) touchant undici (nodejs), undici.
- Probabilité d'exploitation dans les 30 prochains jours (EPSS) : 0.39%, plus élevée que 33.6% des vulnérabilités.
- Correctif : mettre à jour vers 6.28.1, 7.29.1, 8.10.2 ou plus récent.
| Package | Affected versions | Patched versions |
|---|
| undici | ≥ 6.7.0, < 6.28.1≥ 7.0.0, < 7.29.1≥ 8.0.0, < 8.10.2
| 6.28.17.29.18.10.2
|
| undici npm | ≥ 6.7.0, < 6.28.1≥ 7.0.0, < 7.29.1≥ 8.0.0, < 8.10.2
| 6.28.17.29.18.10.2
|
Description
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.
NVD description
undici's WebSocket client crashes the whole Node.js process during the opening handshake when a server responds with a subprotocol that the client never requested. A default WebSocket connection sends no subprotocol, but if the server's 101 response includes a Sec-WebSocket-Protocol header, undici dereferences a null value while checking it against the requested list and throws an uncaught TypeError. Because that code runs inside a microtask with no surrounding error handling, the exception propagates and terminates the process under Node's default behavior, instead of gracefully failing the connection as required by the WebSocket protocol. Any application that opens a WebSocket to an attacker-controlled or compromised server, or over a plaintext connection subject to a machine-in-the-middle, can be crashed remotely without authentication in the default configuration. This affects undici versions from 6.7.0 up to 6.28.1, from 7.0.0 up to 7.29.1, and from 8.0.0 up to 8.10.2. Users should upgrade to undici 6.28.1, 7.29.1, or 8.10.2.
Running one of these products? Scan your site to see whether it exposes a vulnerable version.
Scan my site free