CVE-2026-109855 (GCVE-0-2026-109855)
Vulnerability from cvelistv5
Published
2026-10-15 08:12
Modified
2026-10-15 14:22
CWE
  • CWE-248 - Uncaught Exception
  • CWE-754 - Improper Check for Unusual or Exceptional Conditions
Summary
undici is an HTTP client library for Node.js. In versions 8.11.0 and 8.11.1, its experimental WebSocket client, which is enabled by default when HTTP/2 is allowed, mishandles a failed WebSocket handshake over HTTP/2: the request is already marked completed, so the abort becomes a no-op and the underlying HTTP/2 stream is left open with no error listener. When a malicious server then destroys the connection, the orphaned stream emits an unhandled error and the Node.js process exits. A remote, unauthenticated server can therefore crash any client that opens a WebSocket to it over HTTP/2, resulting in a denial of service. The issue is fixed in undici 8.11.2, and users should upgrade to 8.11.2 or later. As a workaround, set allowH2 to false to disable HTTP/2 for WebSocket connections, or avoid opening WebSocket connections to untrusted servers.
Impacted products
Vendor Product Version
undici undici Version: 8.11.0   ≤
Create a notification for this product.
Show details on NVD website


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