Masimo Data Breach Exposes 61 MB of Customer Info

On April 27, 2025, Masimo Corporation, a global medical technology company, identified unauthorized activity on its on-premise network. According to a disclosure filed with the U.S. Securities and Exchange Commission, Masimo detected the breach and immediately initiated its incident response protocols.

The company proactively isolated affected systems to contain the threat and began a thorough investigation with the help of third-party cybersecurity professionals. Law enforcement was also notified and is actively involved.

The incident impacted Masimo’s manufacturing facilities, causing operations to run at less than normal capacity. As a result, the company’s ability to process, fulfill, and ship customer orders was temporarily disrupted. Masimo is working to restore affected portions of its network and resume normal business operations.

While the full scope and impact of the breach are still under investigation, the company currently believes that its cloud-based systems were not affected. On the dark web, a threat actor known as "almighty4444" claimed responsibility for the attack and posted a sample of allegedly stolen data on September 2, 2024.

The leaked information reportedly includes 61 MB of user data and order details. The types of information exposed may include personally identifiable information (PII) such as names and contact details, as well as order histories.

Masimo's response

Masimo responded quickly by activating its incident response protocols and isolating compromised systems to prevent further unauthorized access. The company engaged external cybersecurity experts to assist with the investigation and remediation efforts, and it has been coordinating with law enforcement throughout the process.

Given the nature of the breach and the potential exposure of personal and order information, individuals who have interacted with Masimo—especially those who have placed orders or registered accounts—should remain vigilant for suspicious emails or communications. It is recommended to monitor accounts for unusual activity, change passwords associated with Masimo accounts, and consider placing fraud alerts with credit bureaus if any financial information was involved.

Masimo has not yet announced specific resources such as dedicated hotlines or credit monitoring for affected individuals. For ongoing updates and official statements, customers can refer to Masimo’s official website.