Horizon3 Triples Valuation to $2B in $250M Series E for AI-Driven Security Validation

Horizon3 provides an autonomous penetration testing platform called NodeZero that enables organizations to continuously test the exploitability of their networks, endpoints, cloud infrastructure, and applications. The company announced a $250 million Series E funding round that triples its valuation to $2 billion.

No lead investors were named in the source material. The funding will fuel Horizon3's mission to lead what it calls the "AI vs. AI cybersecurity era," as demand grows for real-time security validation over traditional point-in-time penetration tests.

NodeZero is used across ITOps, SecOps, security teams, and professional pentesters to autonomously identify and verify attack paths. The platform covers internal and external pentesting, Kubernetes and cloud environments, Active Directory, web applications, and third-party risk management. It also offers risk-based exposure management, security control validation for endpoints, identity, and data, and threat detection and response capabilities including tripwires for Active Directory.

Horizon3 sells into regulated industries including financial services, healthcare, and the US public sector, with a dedicated NodeZero Federal offering. The company also maintains an attack research practice, publishes threat-informed perspectives, and supports a community portal for customers and partners. Its partner ecosystem includes MSSPs, MSPs, and technology alliances.

The Series E follows the company's positioning that traditional annual penetration testing is insufficient against automated and AI-augmented threats. The capital will be deployed to expand the platform's autonomous capabilities and cement its role in continuous security validation.