0sec Labs Open-Sources 0, an AI Security Harness With Web UI, CLI and MCP

Zurich-based 0sec Labs has released 0, an open-source AI security harness.It runs vulnerability investigations, code review, pentesting, reverse engineering and fix generation.Developers drive it from a local browser console, a headless CLI or an MCP server.

The 0sec Labs open-source AI security harness is licensed MIT OR Apache-2.0 and ships as a research preview.TL;DR Wrapper: It is a software harness.Bring your own LLM from 14 listed providers.Runs on: Apple Silicon macOS, x64 or ARM64 Linux, or the ghcr.io/0sec-labs/0 container.No GPU needed.

Model inference runs at your provider.Performance: Strong self-reported CTF scores, plus a public record of upstream Linux kernel fixes.Best: 93/95 (97.9%) on XBOW web CTFs, gpt-5.4 cohort, any-success grouping.Worst: Black-box-only XBOW union of 81/104 (77.9%).A 2026 cold run scored 45/104 (43.3%).

Bottom line: Best: one harness spans web, source, packages, binaries and kernels.Worst: headline scores are self-reported and not [email protected] is 0 from 0sec Labs?0 is a control plane around LLMs and security tools.It is not a model.

You plug in a provider, and 0 runs scoped workflows against authorized targets.The research team describes it as a self-evolving, multi-model harness.0sec Labs is backed by Y Combinator.How does the 0 harness work?The architecture docs state one rule: reproduce before trusting.

Agentic scans follow a conceptual pipeline: Plan, Discover, Attack: a research agent picks vulnerability classes, maps endpoints and tests hypotheses.Triage: filters remove weak findings and check evidence completeness.Verify: a separate session re-exercises each candidate, with 5 turns per finding.

Report: outputs include HTML, PDF, SARIF, Markdown and JSON.Web pentesting is shell-first.The agent uses bash with curl, python3 and sqlmap, not a fixed HTTP tool set.Evidence carries a proof grade from candidate to impact-proven.Compiled targets go through 0verse, a separate in-repo engine.

It wraps Ghidra, angr and AFL++.Its local MCP server exposes 9 tools for scanning, triage, PoVs and reports.How do developers use it?Installation is one script.Running 0 opens the local browser console without an account.

The console has chat, a findings queue and board, workflow templates, skills and memory.Coding agents connect through 0 mcp-server --workflows.The CLI exposes the same workflow runner with commands like 0 workflow run and 0 runs list.Model access is bring-your-own.

The API keys page lists OpenAI, Anthropic, DeepSeek, OpenRouter, Azure, Qwen, Kimi, GLM and Grok.It also supports Claude, Codex and Gemini CLI runtimes.Benchmarks: what do the numbers say?All scores below are self-reported.BenchmarkScoreConditionsXBOW web CTFs93/95 (97.9%)gpt-5.

4 cohort, any retained success countsXBOW union, white-box102/104Retained artifacts, not additiveXBOW union, black-box81/104Retained artifacts, not additiveCybench36/40 (90.0%)Azure gpt-5.4, 3 retriesnpm audit, 81 packagesF1 0.973100% TPR, FPR 0.

11, self-built ground truth The recorded cost was about $5.20 per solved XBOW challenge.window.addEventListener('message',function(e){if(e.data&&e.data.zx0h){var f=document.getElementById('zx0-frame');if(f&&e.source===f.contentWindow){f.style.height=e.data.

zx0h+'px';}}}); How does 0 compare with other open-source AI pentesting tools?Feature0 (0sec Labs)Shannon (Keygraph)StrixCAI (Alias Robotics)LicenseMIT OR Apache-2.0AGPL-3.0Apache-2.

0MIT + proprietary research-onlyStatusResearch previewActiveActiveArchived Aug 28, 2026InterfacesWeb console, CLI, MCP serverCLI, CI actionsCLI, local web viewer, agent skillsCLI/REPL, MCP supportScopeWeb, LLM, MCP, source, packages, binaries, kernelWeb apps and APIs, source requiredCode, web apps, APIsGeneral offensive and defensive automationBinary reverse engineeringYes, 0verse (Ghidra)Not disclosedNot disclosedNot disclosedModelsBYO, 14 listed providersBYO, Anthropic, OpenAI, xAI, Bedrock, localBYO via LiteLLM300+ via LiteLLMRequirementsmacOS (Apple Silicon) or LinuxDocker, Node.

js 18+DockerPython 3.12 recommended What has 0 found in the wild?The research page lists 30+ merged Linux kernel 0-days.Disclosures span Bluetooth, NFC, mac802154, TIPC and mlx5e subsystems.Library CVEs include jsonata, node-forge, protobuf.js and Wireshark.

Availability and pricing The open-source harness is free.You pay your model provider.A hosted version, 0cloud, is on a waitlist.The pricing page lists $100 in trial credits and $5 per PR security test.Key Takeaways 0 is an MIT/Apache-2.0 AI security harness from Y Combinator-backed 0sec Labs.

It ships a browser console, headless CLI and MCP server for coding agents.Bring your own model: 14 providers plus Claude, Codex and Gemini CLIs.Self-reported XBOW score is 93/95; black-box union is 81/104.Check out the GitHub repo, docs and research disclosures.

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