Kevin Mandia's Armadin raises $255.5M Series B at $2.5B+ for autonomous offensive-security agents
Armadin, founded by Mandiant founder Kevin Mandia, raised a $255.5M Series B co-led by a16z and Accel at a valuation above $2.5B (total raised $445M). It builds a swarm of AI agents that attack customers' systems like an adversary would, chaining low-severity weaknesses into validated kill chains.
Key facts
- Series B $255.5M, co-led by Andreessen Horowitz and Accel; new investors Bain Capital Ventures and Redpoint; valuation >$2.5B; total funding $445M
- Product: autonomous agents that chain individually low-severity weaknesses into validated kill chains, from unauthenticated remote code execution through lateral movement to full cloud compromise
- Customers: enterprises and government agencies
What happened
A well-known incident-response founder raised a large round for AI-driven offensive security, the same field that frontier labs are now opening their most cyber-capable models to (Google's Fairwind, OpenAI's Daybreak, Anthropic's Glasswing).
Why it matters
Investors are betting that autonomous attack agents will become standard defensive tooling, now that frontier models have crossed critical cyber thresholds.
Changelog
- 2026-10-01: created (sweep 2026-10-01, Techmeme/Reuters)
Related events
Sources (3)
- pressReuters: AI cybersecurity startup Armadin valued over $2.5 billion
- pressSecurityWeek: Kevin Mandia's Armadin raises $255 million at $2.5 billion valuation
- pressHelp Net Security: Armadin raises $255.5 million
id: 2026-10-01-armadin-255m-series-b · updated 2026-10-01 · open in the interactive timeline