Armadin Raises $255.5M Series B at Over $2.5B Valuation to Scale Its Agentic Security Platform

Armadin, an AI-native cybersecurity company, announced on October 1, 2026 that it has raised $255.5 million in Series B funding co-led by Andreessen Horowitz and Accel, a round the company said values it at over $2.5 billion.

New investors Bain Capital Ventures and Redpoint participated in the round, and existing investors 8VC, Ballistic Ventures, Google Ventures, In-Q-Tel, Kleiner Perkins, and Menlo Ventures also returned. Armadin said the financing brings its total funding to $445 million, and that it will use the investment to scale its agentic security platform along with its research, training, and go-to-market efforts. The company confirmed the raise and the stated uses in a post on its own newsroom dated October 1, 2026.

Agentic Attack Campaigns in Production

Seven months after emerging from stealth, Armadin said it is running agentic attack campaigns in production for Fortune 500 enterprises and government customers.

Armadin said frontier AI models compress the time between vulnerability disclosure and a working exploit, and that periodic penetration tests cannot keep pace with that cycle. Scanner output, the company said, fails in a different way because it scores each finding in isolation rather than showing how weaknesses connect.

Armadin describes deploying an autonomous swarm of specialized agents that reason like a skilled adversary across an organization’s attack surface. The agents chain individually low-severity weaknesses into validated kill chains that, according to the company, can run from unauthenticated remote code execution at the perimeter through lateral movement to full cloud compromise. Security teams, Armadin said, see the exact attack paths an adversary would use in production, along with the blast radius of each, and can sever those paths before they are exploited.

Statements From the CEO and Co-Lead Investors

“Offense is uniquely advantaged right now,” said Kevin Mandia, Armadin’s CEO, in the announcement. “AI lets an attacker find and chain weaknesses faster than any human team can respond.” Mandia said the only way to build a defense that keeps pace is to train it against the best offense available every day, and that with a16z and Accel co-leading, Armadin will put that offense to work for the enterprises and government agencies defending what he called the world’s most critical systems.

Accel partner Ping Li said the firm led Armadin’s Series A on the conviction that, against agentic adversaries, the best defense is a strong offense powered by AI, and that the need has only grown more pressing. Li said that in less than a year Armadin has set the standard for AI-powered offensive security and remediation across enterprises and governments.

Andreessen Horowitz general partner David George said every major platform shift creates a new generation of security leaders and described AI as the biggest shift yet. He said Mandia has been on the front lines of the most consequential breaches in history and has built a team pairing elite red teamers with world-class AI engineers. “We invested because we believe Armadin will become the defining security company of the AI era,” George said.

Stealth Exit and Earlier Funding

Armadin publicly launched on March 10, 2026, announcing $189.9 million in combined seed and Series A funding. Accel led that financing, with participation from Google Ventures, Kleiner Perkins, Menlo Ventures, and In-Q-Tel, and follow-on investment from 8VC and Ballistic Ventures. In its launch release, the company characterized the raise as the largest combined seed and Series A funding round in cybersecurity history.

At launch, the company described the rise of AI-powered attackers as ushering in what it calls Hyperattacks: sophisticated, multi-modal campaigns that move at machine speed, which it said human-led defenses are no longer fast enough to counter. Its platform pairs specialized AI agents with custom models in what it calls an agentic attacker swarm that continuously reasons, plans, and adapts like advanced human threat actors, providing executives and boards with what the company describes as decision-grade proof of what can actually be exploited.

Mandia, who leads the company alongside founders Travis Lanham, its chief technology officer, Evan Peña, its chief offensive security officer, and David Slater, said at the launch that defense must become autonomous in a world of machine-speed attacks. Peña said at the time that Armadin was reinforcing decades of human-led red teaming expertise into AI models that were outpacing the company’s human operators. Lanham described the goal as building an attacker that reasons and learns rather than following a script, trained to the standards of a world-class red team with safety at the foundation.