CVE-2026-19534

A flaw was found in undici. A remote attacker can exploit this vulnerability by responding with an unrequested WebSocket subprotocol during the opening handshake. This causes the undici WebSocket client to crash the entire Node.js process, leading to a denial of service (DoS).

This is an Important denial of service flaw in undici's WebSocket client, which can lead to a Node.js process crash. The vulnerability is triggered when an application connects to a malicious or compromised server that responds with an unrequested WebSocket subprotocol, allowing a remote, unauthenticated attacker to cause a denial of service in affected Red Hat products.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.