CVE-2025-29953: Deserialization of Untrusted Data Vulnerability in Apache ActiveMQ NMS OpenWire Client

A critical security vulnerability, labeled as CVE-2025-29953, has been identified in older versions (before 2.1.1) of the Apache ActiveMQ NMS OpenWire Client. This vulnerability is related to the deserialization of untrusted data, which can potentially lead to arbitrary code execution when clients establish connections to untrusted servers. In this blog post, we will discuss the details of this vulnerability, review a code snippet demonstrating the flaw, provide links to the original references, and offer recommendations on how to mitigate the risks associated with this vulnerability.

Vulnerability Details

The vulnerability in question was introduced in version 2.1. of Apache ActiveMQ NMS OpenWire Client when a new feature, called "allow/denylist," was added to help restrict deserialization permissions. However, this feature could be bypassed by malicious servers, leading to unbounded deserialization and putting client systems at risk.

Affected Systems

This vulnerability affects Apache ActiveMQ NMS OpenWire Client systems before version 2.1.1 when performing connections to untrusted servers.

Exploit Details

An attacker exploiting CVE-2025-29953 could craft a malicious server response that bypasses the allow/denylist feature, leading to the unbounded deserialization of data in the client system. This could then allow the attacker to execute arbitrary code on the targeted device.

Code Snippet

The following code snippet demonstrates how to connect to an Apache ActiveMQ NMS OpenWire Client and perform deserialization.

using System;
using Apache.NMS;
using Apache.NMS.ActiveMQ;
using Apache.NMS.Util;

public class ActiveMQOpenWire {
  public static void Main(string[] args) {
    Uri connectURI = new Uri("tcp://localhost:61616");
    IConnectionFactory factory = new ConnectionFactory(connectURI);
    using (IConnection connection = factory.CreateConnection()) {
      using (ISession session = connection.CreateSession()) {
        IDestination destination = SessionUtil.GetDestination(session, "queue://test");
        using (IMessageConsumer consumer = session.CreateConsumer(destination)) {
          connection.Start();
          IMessage receivedMessage = consumer.Receive(TimeSpan.FromSeconds(10));
          if (receivedMessage == null) {
            Console.WriteLine("No message received");
          } else {
            // Perform deserialization here, may cause the vulnerability to occur
            Console.WriteLine("Received message: " + receivedMessage);
          }
        }
      }
    }
  }
}

Original References

1. Official CVE details: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-29953
2. Apache ActiveMQ NMS OpenWire Client source code repository: https://github.com/apache/activemq-nms-openwire
3. Apache ActiveMQ NMS OpenWire Client version 2.1.1 release notes: https://activemq.apache.org/components/nms/releasenotes.html

Mitigation Recommendations

Users of Apache ActiveMQ NMS OpenWire Client are advised to take the following steps immediately to protect their systems:

Update to version 2.1.1 or later to resolve the vulnerability.

2. Move away from using .NET binary serialization as a precautionary measure to harden your system against potential future threats. This is especially relevant since the .NET team has deprecated the built-in .NET binary serialization feature, starting with .NET 9, and is recommending migrating away from binary serialization.

Conclusion

CVE-2025-29953 is a critical vulnerability affecting Apache ActiveMQ NMS OpenWire Client systems before version 2.1.1. To prevent unauthorized deserialization of untrusted data, update to the latest version of Apache ActiveMQ NMS OpenWire Client and consider migrating away from binary serialization. Stay vigilant about potential future issues and always keep your systems up-to-date.

Timeline

Published on: 04/18/2025 16:15:22 UTC
Last modified on: 04/23/2025 16:15:47 UTC