Undertow: out-of-memory error after several closed connections with wildfly-http-client protocol

Summary

A vulnerability was found in Undertow. This vulnerability impacts a server that supports the wildfly-http-client protocol. Whenever a malicious user opens and closes a connection with the HTTP port of the server and then closes the connection immediately, the server will end with both memory and open file limits exhausted at some point, depending on the amount of memory available. At HTTP upgrade to remoting, the WriteTimeoutStreamSinkConduit leaks connections if RemotingConnection is closed by Remoting ServerConnectionOpenListener. Because the remoting connection originates in Undertow as part of the HTTP upgrade, there is an external layer to the remoting connection. This connection is unaware of the outermost layer when closing the connection during the connection opening procedure. Hence, the Undertow WriteTimeoutStreamSinkConduit is not notified of the closed connection in this scenario. Because WriteTimeoutStreamSinkConduit creates a timeout task, the whole dependency tree leaks via that task, which is added to XNIO WorkerThread. So, the workerThread points to the Undertow conduit, which contains the connections and causes the leak.

Timeline

1. Feb 19, 2024, 9:23 PM UTCCVE published
2. Feb 22, 2024, 4:54 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Oct 7, 2026, 9:29 PM UTCRecord last updated

Affected versions

• undertow

  1.31.0

• Red Hat Red Hat build of Apache Camel 4.4.1 for Spring Boot 3.2

  Version range not reported

• Red Hat Red Hat Fuse 7.13.0

  Version range not reported

• eap7-activemq-artemis

  Version range not reported

• eap7-artemis-native

  Version range not reported

• eap7-jboss-xnio-base

  Version range not reported

• eap7-jsoup

  Version range not reported

• eap7-undertow

  Version range not reported

• eap7-wildfly

  Version range not reported

• eap7-woodstox-core

  Version range not reported

• eap7-xml-security

  Version range not reported

• eap7-jackson-annotations

  Version range not reported

• eap7-jackson-core

  Version range not reported

• eap7-jackson-databind

  Version range not reported

• eap7-jackson-jaxrs-providers

  Version range not reported

• eap7-jackson-modules-base

  Version range not reported

• eap7-jackson-modules-java8

  Version range not reported

• eap7-jboss-server-migration

  Version range not reported

• eap7-netty

  Version range not reported

• eap7-undertow

  Version range not reported

• eap7-wildfly

  Version range not reported

• eap7-wildfly-elytron

  Version range not reported

• io.undertow/undertow-core

  Version range not reported

• eap7-undertow

  Version range not reported

• eap7-undertow

  Version range not reported

• eap7-undertow

  Version range not reported

• rh-sso7-keycloak

  Version range not reported

• rh-sso7-keycloak

  Version range not reported

• rh-sso7-keycloak

  Version range not reported

• rh-sso-7/sso76-openshift-rhel8

  Version range not reported

• undertow

  Version range not reported

• undertow

  Version range not reported

• undertow

  Version range not reported

• undertow

  Version range not reported

• undertow

  Version range not reported

• undertow

  Version range not reported

• undertow

  Version range not reported

• undertow

  Version range not reported

• quarkus-undertow

  Version range not reported

• undertow

  Version range not reported

• undertow

  Version range not reported

• undertow

  Version range not reported

• undertow

  Version range not reported

• undertow-core

  Version range not reported

• undertow

  Version range not reported

• undertow

  Version range not reported

• undertow

  Version range not reported

• io.undertow:undertow-coreMaven

  From 2.3.0.Final · fixed in 2.3.12.Final

• io.undertow:undertow-coreMaven

  fixed in 2.2.31.Final

References 15