CVE-2026-81624

Undertow is a flexible performant web server used in JBoss EAP and WildFly. A flaw was found in how Undertow handles WebSocket connections. Specifically, certain configuration limits like message buffer sizes and session timeouts cannot be adjusted and default to being unlimited. This allows a remote attacker to send large amounts of data or maintain connections indefinitely, potentially crashing the server by exhausting its memory or other resources.

The Red Hat Product Security team has assessed the severity of this vulnerability as Important, given that the default configuration allows for unlimited resource consumption. Successful exploitation allows an attacker to cause a denial of service via resource exhaustion. The vulnerability's root cause is the lack of configuration options for WebSocket buffer sizes and timeouts in the container boot process.

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.