GHSA-rfgv-xxqx-mfg5
undici vulnerable to Denial of Service via unrequested WebSocket subprotocol
Quick fix
GHSA-rfgv-xxqx-mfg5 — undici: upgrade to the fixed version with the command below.
npm install undici@6.28.1Details
### 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.
Are you affected?
Enter the version of the package you're using.
Affected packages
References
- https://github.com/nodejs/undici/security/advisories/GHSA-rfgv-xxqx-mfg5[WEB]
- https://nvd.nist.gov/vuln/detail/CVE-2026-19534[ADVISORY]
- https://github.com/nodejs/undici/commit/2af0faf88b906d3127a360c3ac75164c0f95e5a5[WEB]
- https://github.com/nodejs/undici/commit/6615e0175e9b635bcd2e3e87a47daa82f6f5b728[WEB]
- https://github.com/nodejs/undici/commit/66e12816064cf3068f63bd134748b7fc4e779bad[WEB]
- https://cna.openjsf.org/security-advisories.html[WEB]
- https://github.com/nodejs/undici[PACKAGE]
- https://github.com/nodejs/undici/releases/tag/v6.28.1[WEB]
- https://github.com/nodejs/undici/releases/tag/v7.29.1[WEB]
- https://github.com/nodejs/undici/releases/tag/v8.10.2[WEB]