CVE-2025-29953
📋 TL;DR
This vulnerability allows malicious Apache ActiveMQ servers to send specially crafted responses to NMS OpenWire clients, leading to arbitrary code execution on client systems through deserialization attacks. It affects all Apache ActiveMQ NMS OpenWire Client versions before 2.1.1 when connecting to untrusted servers. The vulnerability is critical with a CVSS score of 9.8.
💻 Affected Systems
- Apache ActiveMQ NMS OpenWire Client
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of client systems with remote code execution, potentially leading to data theft, lateral movement, and full system control.
Likely Case
Attackers hosting malicious ActiveMQ servers to exploit clients connecting to them, resulting in client system compromise.
If Mitigated
Limited impact with proper network segmentation and client-server trust relationships, though risk remains if connecting to untrusted servers.
🎯 Exploit Status
Exploitation requires client to connect to malicious server. The vulnerability bypasses the allow/denylist feature introduced in version 2.1.0.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.1.1
Vendor Advisory: https://lists.apache.org/thread/vc1sj9y3056d3kkhcvrs9fyw5w8kpmlx
Restart Required: Yes
Instructions:
1. Identify all systems using Apache ActiveMQ NMS OpenWire Client. 2. Update to version 2.1.1 or later. 3. Restart all affected applications/services. 4. Consider migrating away from .NET binary serialization as recommended.
🔧 Temporary Workarounds
Restrict Client Connections
allOnly allow NMS OpenWire clients to connect to trusted, internal ActiveMQ servers
Implement network segmentation and firewall rules to restrict outbound connections from clients
Disable Binary Serialization
allMigrate to alternative serialization methods as recommended by .NET team
Modify application code to use JSON, XML, or other serialization formats instead of .NET binary serialization
🧯 If You Can't Patch
- Implement strict network controls to prevent clients from connecting to untrusted ActiveMQ servers
- Monitor for suspicious outbound connections from NMS OpenWire clients to unknown servers
🔍 How to Verify
Check if Vulnerable:
Check the version of Apache.NMS.ActiveMQ.dll in your application. Versions before 2.1.1 are vulnerable.Check Version:
On Windows: [System.Reflection.Assembly]::LoadFile('path\to\Apache.NMS.ActiveMQ.dll').GetName().VersionVerify Fix Applied:
Verify the assembly version is 2.1.1.0 or higher and test connectivity to ensure functionality is maintained.📡 Detection & Monitoring
Log Indicators:
- Deserialization errors in application logs
- Unexpected process creation from NMS client processes
Network Indicators:
- NMS OpenWire clients connecting to unknown/untrusted servers
- Unusual outbound traffic patterns from client systems
SIEM Query:
source="application_logs" AND ("deserialization" OR "Apache.NMS") AND (error OR exception)