Autonomous AI pentesters that find and exploit vulnerabilities using 150+ security tools.
Using autonomous exploit generation with LLM agents, multi-agent attack chain orchestration via FastMCP, and continuous security feedback loops from real-world testing.

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Cyber Security
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YC W26

Last Updated:
March 19, 2026

Builds an autonomous offensive security platform using LLM-powered multi-agent orchestration (Claude, GPT, DeepSeek) and FastMCP protocol to continuously discover, exploit, and validate vulnerabilities across web apps, APIs, and infrastructure.
Continuous autonomous penetration testing, real-time vulnerability dashboards with CVSS scoring, 150+ professional security tool integration, AI-generated exploits including zero-day detection, developer-workflow integration.
Adaptive multi-agent attack chains, browser automation agents, API-specific testing. FastMCP protocol for community-contributed tool integrations. CI/CD pipeline integrations and compliance automation (SOC 2, ISO 27001) coming. $3B+ in prevented damages claimed across YC companies.
<p>AI agents autonomously generate and validate exploits for newly discovered vulnerabilities, including zero-days, without human intervention.</p>
An AI agent reads about a new software flaw and instantly figures out how to break in, then proves it actually works—before any attacker can.
Hex Security's AIExploitGenerator agent leverages large language models (Claude, GPT, DeepSeek) combined with real-time CVE intelligence feeds to autonomously craft, test, and validate exploits for emerging vulnerabilities. When a new CVE is published or a novel attack vector is identified during a scan, the agent analyzes the vulnerability context, generates candidate exploit payloads, and executes them within isolated Docker/Kali Linux containers to confirm exploitability. The system achieves a 98.7% detection rate with only a 2.1% false positive rate by iterating through multiple exploit strategies, learning from failed attempts, and adapting payloads in real time. Results are surfaced as actionable vulnerability cards with CVSS scores and remediation steps, enabling security teams to patch confirmed threats within hours rather than weeks. This eliminates the traditional bottleneck of waiting for human researchers to develop proof-of-concept exploits.
It's like having a locksmith who reads about a new lock design in the morning paper and by lunchtime has already picked it, documented the weakness, and handed you a better deadbolt.
<p>Multiple specialized AI agents collaborate to autonomously plan, execute, and adapt complex multi-step attack chains across an organization's entire attack surface.</p>
A team of AI specialists—one scouts the perimeter, another picks the locks, a third escalates access—all coordinating like a heist crew that never sleeps.
Hex Security's platform employs a multi-agent architecture where specialized agents (IntelligentDecisionEngine, AIExploitGenerator, reconnaissance agents, browser automation agents, API testing agents) collaborate through the FastMCP protocol to execute end-to-end attack simulations. The IntelligentDecisionEngine acts as the strategic coordinator, mapping high-level operator intent (e.g., "test this web application for authentication bypass vulnerabilities") into a sequence of technical steps distributed across specialized agents. Each agent handles a distinct phase—reconnaissance (Nmap, Shodan), vulnerability scanning, exploitation, privilege escalation, and lateral movement—while sharing context and findings in real time. When an agent encounters an unexpected defense or failure, it reports back to the decision engine, which dynamically re-plans the attack chain, selects alternative tools or techniques, and retries with adapted strategies. This closed-loop, adaptive orchestration enables Hex Security to simulate sophisticated, multi-stage attacks that mirror real-world adversary behavior continuously, without human intervention, across web apps, APIs, and infrastructure simultaneously.
It's like an Ocean's Eleven crew where every member is an AI—one cases the joint, one cracks the safe, one handles the getaway—and if the plan goes sideways, they rewrite the script on the fly without ever calling the director.
<p>AI agents integrate into development workflows to continuously test code changes for security vulnerabilities and deliver real-time, developer-friendly remediation guidance.</p>
Every time a developer pushes new code, an AI security agent instantly attacks it, finds the weak spots, and tells the developer exactly how to fix them—before customers ever see it.
Hex Security's platform is designed to embed autonomous offensive security directly into the software development lifecycle. When integrated into CI/CD pipelines, AI agents are triggered by code commits, pull requests, or deployment events to automatically launch targeted penetration tests against the changed application surfaces. The agents perform contextual analysis of the code changes, prioritize testing on newly introduced or modified endpoints, and execute attack simulations tailored to the specific technology stack (e.g., testing for SQL injection on new database queries, SSRF on new API integrations, authentication bypass on modified auth flows). Results are delivered as developer-friendly vulnerability cards within existing tools (e.g., GitHub issues, Jira tickets, Slack notifications), each containing a plain-language explanation of the vulnerability, its CVSS score, proof-of-exploit evidence, and step-by-step remediation code suggestions. This creates a continuous feedback loop where security findings are surfaced to the developers who introduced them, at the moment they can most easily fix them, dramatically reducing the cost and time of remediation compared to traditional post-deployment pentesting cycles.
It's like having a brutally honest code reviewer who doesn't just say "this looks wrong" but actually breaks into your app live, shows you the footage, and hands you the exact patch—all before your PR is merged.
FastMCP protocol orchestrating 150+ tools under LLM agents, with direct access to hundreds of YC portfolio companies as live testing grounds. Creates a unique feedback loop of real-world vulnerability data.