CVE Tools

CVE-2024-1635

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

No known exploitation. EPSS puts it in the 91st percentile. A vendor fix is available.

Published Updated Sources: CVE.org, NVD, GitHub

What to do

The vendor has published a fix. Version details are below where the sources state them.

What it is

From the CVE record

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.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS91st
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

4.6% chance of exploitation activity in the next 30 days, which ranks it in the 91st percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

14 events over 897 days, from the signal feeds we watch.

  1. Patch availablepatch available, workaround available, workaround available, record updated, record updated
  2. EPSS band changemoderate → low
  3. EPSS band changelow → moderate
  4. Patch availableworkaround available, record updated
  5. Publishedweakness classified, att&ck mapped

Affected products

Technical detail

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Scored 7.5 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality NoneNo confidentiality impact
  • Integrity NoneNo integrity impact
  • Availability HighTotal denial of service — the component is completely unavailable

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

Watch the software you run.

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We'll flag the next CVE, public exploit or patch for Red Hat, not every advisory.

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