{"id":"DEBIAN-CVE-2026-109855","details":"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.","modified":"2026-10-16T06:00:07.257042926Z","published":"2026-10-15T09:17:16.573Z","upstream":["CVE-2026-109855"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-109855"}],"affected":[{"package":{"name":"node-undici","ecosystem":"Debian:14","purl":"pkg:deb/debian/node-undici?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["7.15.0+dfsg+~cs3.2.0-1","7.15.0+dfsg+~cs3.2.0-3","7.16.0+dfsg+~cs3.2.0-1","7.16.0+dfsg+~cs3.2.0-2","7.18.2+dfsg+~cs3.2.0-1","7.24.5+dfsg+~cs3.2.0-1","7.24.6+dfsg+~cs3.2.0-1","7.24.6+dfsg+~cs3.2.0-2","7.24.6+dfsg+~cs3.2.0-3","7.3.0+dfsg1+~cs24.12.11-1","7.3.0+dfsg1+~cs24.12.11-2","8.10.2+dfsg+~cs3.2.2-1","8.12.1+dfsg+~cs3.2.3-1","8.5.0+dfsg+~cs3.2.0-1","8.5.0+dfsg+~cs3.2.0-2","8.5.0+dfsg+~cs3.2.0-3","8.9.0+dfsg+~cs3.2.0-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-109855.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}