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High7.5Red Hat Linux

High [CVE-2024-1635] Undertow: out-of-memory error after several closed connections with wildfly-http-client protocol

This high-severity Red Hat Linux advisory covers CVE-2024-1635 affecting Red Hat JBoss Enterprise Application Platform 7.1 EUS for RHEL 7, Red Hat JBoss Enterprise Application Platform 7.3 EUS for RHEL 7, Red Hat JBoss Enterprise Application Platform 7.4 for RHEL 8.

CVE-2024-1635 Published Feb 19, 2024Updated by vendor Aug 4, 2026
Affected products & platforms
Red Hat LinuxRed Hat Enterprise Linux
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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.

Affected versions
  • 1.31.0

Official advisory · high-confidence parse· fetched 2 hours ago·verify at source

Fixed versions

No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.

Official advisory · high-confidence parse· fetched 2 hours ago·verify at source

Mitigation checklist

Recommended fix / mitigation
  • 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.

Official advisory · high-confidence parse· fetched 2 hours ago·verify at source

Discussion(0)

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