Originally published on NextFuture

Anthropic's Mythos and OpenAI's GPT-5.5-Cyber sit behind allowlists covering fewer than 200 organizations as of May 2026. These five tools — open weights, hosted APIs, and self-hostable stacks — address the same defensive surface area with no application required. For full context on why the frontier cyber models are restricted, see Inside the AI Cyber Arms Race (May 2026) .

TL;DR: The 2026 winners

ToolBest ForHostingStarts AtAllowlist?

Llama Guard 3 (8B)Content filtering at app layerSelf-host / HF Inference APIFree / $0.0004 per 1k tokensNo

SentinelSphere 2.1Real-time agent threat detectionCloud SaaS$49/mo StarterNo

Google Cloud Security AI WorkbenchCloud log triage and forensicsGCP managed~$0.12 per 1k security eventsNo

CyberSecEval 3Pre-deploy LLM capability evaluationSelf-host (GitHub, Apache 2.0)FreeNo

Microsoft PyRIT + OWASP LLM Top 10 v2Prompt red-teaming and threat modelingSelf-host (pip install)FreeNo

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