CVE-2026-109855
Fixed in a distro release EPSS <1%CVSS 7.5
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.
Products: undici
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Debian 14 | node-undici | no fix |
| Red Hat hummingbird 1 | grafana12.4 | 0:12.4.12-0.4.hum1 |
| Red Hat hummingbird 1 | nodejs26 | 0:26.11.1-0.3.hum1 |
| Red Hat hummingbird 1 | nodejs26-bin | 0:26.11.1-0.3.hum1 |
| Red Hat hummingbird 1 | nodejs26-devel | 0:26.11.1-0.3.hum1 |
| Red Hat hummingbird 1 | nodejs26-docs | 0:26.11.1-0.3.hum1 |
| Red Hat hummingbird 1 | nodejs26-full-i18n | 0:26.11.1-0.3.hum1 |
| Red Hat hummingbird 1 | nodejs26-libs | 0:26.11.1-0.3.hum1 |
| Red Hat hummingbird 1 | nodejs26-npm | 0:11.20.0-1.26.11.1.0.3.hum1 |
| Red Hat hummingbird 1 | nodejs26-npm-bin | 0:26.11.1-0.3.hum1 |
| Ubuntu 24.04 LTS | node-undici | no fix |
| Ubuntu 26.04 LTS | node-undici | no fix |
| Ubuntu 26.10 | node-undici | no fix |