Critical Apache ActiveMQ Vulnerability Allows Remote Code Execution -

A serious security flaw has been discovered in Apache ActiveMQ’s .NET Message Service (NMS) library. This vulnerability, tracked as CVE-2025-29953, could allow remote attackers to run malicious code on systems that haven’t been updated.

With a high CVSS score of 8.1, the flaw affects all versions of ActiveMQ before the latest security patch.

Critical Apache ActiveMQ Vulnerability

Key Details

Vulnerability Name: Apache ActiveMQ NMS Body Deserialization RCE
CVE ID: CVE-2025-29953
CVSS Score: 8.1 (High)
Affected Product: ActiveMQ (NMS Library)
Type: Remote Code Execution (RCE) via Deserialization

The vulnerability lies in the Body accessor method of the NMS library. When handling messages, the library fails to properly validate serialized data within the message body. As a result, an attacker can inject malicious payloads that trigger code execution once the message is deserialized on the server side.

This vulnerability is particularly dangerous because:

No authentication is required – attackers can exploit the flaw without logging in or having access credentials.
No user interaction is needed – once the server processes the message, the attack can be triggered automatically.
ActiveMQ is widely used – many enterprises rely on ActiveMQ for cloud messaging, IoT systems, and microservice architectures, increasing the attack surface.

How the Exploit Works– Apache ActiveMQ Vulnerability

Deserialization vulnerabilities occur when an application mistakenly trusts and processes unverified data. In this case:

An attacker crafts a specially designed message that contains a malicious object.
This message is sent to an ActiveMQ instance using the NMS library.
When the server accesses the Body property of that message, it deserializes the content.
The deserialization process runs the attacker’s payload as executable code within the ActiveMQ server’s context.

If successful, this could lead to:

Complete remote takeover of the server
Data breaches or data manipulation
Deployment of ransomware or other malware
Lateral movement inside enterprise networks

All versions of Apache ActiveMQ NMS prior to the April 30, 2025 security update are vulnerable. Organizations using ActiveMQ in .NET-based environments are particularly at risk.

Mitigation and Recommendations

Apache strongly advises all users to update ActiveMQ to the latest version, which fixes the deserialization flaw by adding stricter data validation.

To further protect your systems:

Limit external access – Don’t expose ActiveMQ to the internet unless absolutely necessary.
Monitor logs – Look out for unusual activity like deserialization errors or unexpected remote connections.
Audit custom integrations – Review any use of the NMS library for potential weak points.

This issue highlights the ongoing risk in messaging systems that support critical sectors like healthcare, finance, and logistics.

“Deserialization flaws are among the most dangerous vulnerabilities,” says ZDI analyst Mark Rivers. “Patching and proper network controls are key to stopping serious breaches.”

Admins are urged to act quickly, as exploits for similar bugs often surface shortly after public disclosure.