Enterprise AI security platform Rein Security has announced a $25 million Series A funding round, bringing the company’s total funding to $35 million.
According to a report by Gartner, the market for securing AI is expected to reach nearly $4.8 billion in 2027, representing a 68.7% increase compared to 2026, and expand to almost $7.7 billion by 2028. The funding round was co-led by Glilot Capital and Sienna Venture Capital, with participation from Corner Ventures, Atlacle, and RNP Capital Advisors.
The company has offices in Tel Aviv and New York and employs a team of 31 people.
The current financing round comes as many organizations rapidly deploy AI agents with extensive access to business systems, corporate databases, and routine workflows. This shift creates significant new security risks that traditional approaches are no longer equipped to handle effectively.
As enterprise adoption accelerates and agents operate autonomously, organizations face a dual challenge: securing internal systems against operational failures and preventing sophisticated AI-based attacks by hostile actors.
Rein Security’s platform is built on patented sidecar technology that operates at runtime directly at the agents’ execution point. This mechanism provides security teams with full visibility into every line of code and accessible resource in the enterprise environment. It delivers control and precise real-time blocking against harmful activities, offering comprehensive supply chain protection without routing sensitive information through external gateways or proxies that could expose corporate data.
Matan Bar-Efrat, co-founder and CEO of the company, noted that AI agents are replacing critical processes while security architectures struggle to keep pace, adding that the capital will enable Rein Security to continue developing the infrastructure needed for safe deployment. Organizations must transition from passive vulnerability management to proactive defense and prevention against attacks moving at machine speed.
Arik Kleinstein, founding partner at Glilot Capital, emphasized that the technology represents a fundamental shift requiring close, continuous oversight of autonomous agents operating without human intervention.
The threats the company targets are visible in complex operational environments. At the Black Hat USA 2026 conference, the company’s research team, Agent Breakers, presented a sophisticated exploit of an AI shopping agent used by a major American corporation, demonstrating how new systems bypass traditional security controls. Additionally, prompt injection hidden inside a routine customer onboarding PDF was detected at another global organization; the platform blocked the attempt to divert the agent from its intended purpose before damage occurred.
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