CVE-2026-12151

A flaw was found in undici. A malicious WebSocket server can exploit this by streaming numerous small or empty continuation frames. This can bypass per-frame and cumulative-size validation, leading to unbounded memory growth in the client process. The primary consequence is memory exhaustion, resulting in a denial of service (DoS) for affected applications using the undici WebSocket client or WebSocketStream API.

This Important denial of service flaw in the undici WebSocket client allows a remote attacker to cause unbounded memory growth. By sending numerous small or empty WebSocket frames, an unauthenticated attacker can exhaust system memory, leading to a denial of service in Red Hat products that use the affected client.

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.