AI Security
23 October 2026•11 min read•By Roman Silantev

Top 11 Open Source AI Security Tools for AI Agents (2026)

Australian businesses are installing agent skills and MCP servers written by strangers on GitHub, then giving them access to code, inboxes and client data. Here are 11 open source tools that audit code, find vulnerabilities, run AI pentests and check the agents themselves, with our honest take on each.

Top 11 Open Source AI Security Tools for AI Agents (2026)

Top 11 Open Source AI Security Tools for AI Agents (2026)

The risk nobody puts in the launch post

When your developer types one command to add a "skill" to Claude Code, Codex or Cursor, they're handing a stranger's instructions to software that can read your repo, run terminal commands and call your APIs. Same with MCP servers, the plug-ins that connect AI agents to your tools and data.

Most of the time it's fine. Some of the time it isn't. NVIDIA's SkillSpector team says that in a research set of 31,132 skills, 26.1% contained vulnerabilities and 5.2% showed likely malicious intent. Their number, not ours, but it's a useful reality check.

The security community has been busy. We checked every repo below on 23 October 2026. Each one exists, sits under the organisation you'd expect, and the star counts are current. Stars measure popularity, not safety. The cards under each tool are the live GitHub repository previews.

The 11 tools at a glance

#ToolWhat it is forLicenceStars
1Cloudflare Security Audit SkillRepeatable code audits inside a coding agentMIT~40k
2NVIDIA SkillSpectorScan a skill before you install itApache 2.0~21k
3Snyk Agent ScanFind agents, skills and MCP servers already on a machineApache 2.0~3.2k
4Cisco AI Defense Skill ScannerScan shared skills in CI before mergeApache 2.0~2.6k
5SAST SkillsCheap first-pass static scan from a coding assistantMIT~1.3k
6StrixAI pentest of a running app, with proof of conceptApache 2.0~71k
7ShannonSource-aware web and API pentest. No exploit, no reportAGPL-3.0~49k
8PentAGISelf-hosted multi-agent pentest, including local modelsMIT~32k
9PentestGPTStaged pentest co-pilot, with published researchMIT~16k
10HexStrike AIMCP server that hands an agent 150+ offensive toolsMIT~13k
11PentestAgentBlack-box and bug-bounty agent, with a human in the loopMIT~3.2k

Star counts are as of October 2026.

Part 1: Security audits and agent skills

These tools either turn your coding agent into a security reviewer, or check the skills and MCP servers you're about to install. If you only read half of this article, read this half.

1. Cloudflare Security Audit Skill

GitHub repository card for cloudflare/security-audit-skill

What it does

Turns your coding agent into a structured security auditor. It runs six phases: reconnaissance, bug hunting, validation by a separate agent that tries to disprove each finding, structured output, independent re-verification and a final report. Cloudflare says it's the skill that seeded its own internal vulnerability discovery harness.

Who it's for

Dev teams and agencies that own a codebase and want a repeatable audit.

Our take

Where we'd start for code review. The agent that checks a finding is never the one that found it, and severity needs real impact. Two caveats. It wants a sandbox with networking switched off before it executes target code. And Cloudflare says a single run found roughly half of what repeated runs found, so budget for several passes and the model costs.

Licence: MIT. Stars: about 40k as of October 2026.

View on GitHub

2. NVIDIA SkillSpector

GitHub repository card for NVIDIA/SkillSpector

What it does

Scans AI agent skills before you install them. It checks a repo, URL, zip or folder against 71 patterns across 17 categories, including prompt injection, data exfiltration, privilege escalation, supply chain risk and MCP tool poisoning. Static analysis first, optional LLM review second, dependency lookups against OSV.dev, and a 0 to 100 risk score.

Who it's for

Anyone whose staff install skills, from a solo developer to an IT team.

Our take

If your team uses skills at all, put this in the install process. NVIDIA uses it in its own pipeline for vetting skills, which is a decent sign it's built for real use. A low score isn't a guarantee, though. A clever attacker writes instructions that look boring. It catches the obvious and the lazy. A human still reads anything touching credentials.

Licence: Apache 2.0. Stars: about 21k as of October 2026.

View on GitHub

3. Snyk Agent Scan

GitHub repository card for snyk/agent-scan

What it does

Finds the agent harnesses, MCP servers and skills already installed on a machine and scans them for prompt injection, sensitive data handling and malware hidden in natural language. It grew out of Invariant Labs' MCP-Scan research.

Who it's for

IT teams who want to know what's actually running on developer laptops.

Our take

Great for the "what have we got?" audit, which is where we start with most new clients. Read the README warning: to get tool descriptions, it starts the MCP servers in your config. Scanning an untrusted server can run that server, so do it in a container or throwaway VM. Snyk also calls the CLI output experimental.

Licence: Apache 2.0. Stars: about 3.2k as of October 2026.

View on GitHub

4. Cisco AI Defense Skill Scanner

GitHub repository card for cisco-ai-defense/skill-scanner

What it does

Checks third-party agent skills for prompt injection, data exfiltration and malicious code before installation, using pattern rules, dataflow analysis and an optional LLM judge. Outputs SARIF and ships a GitHub Actions workflow and pre-commit hook.

Who it's for

Teams keeping shared skills in a repo who want every change scanned in CI.

Our take

We like that Cisco is honest. The README calls it "best-effort" and says no findings doesn't mean no risk. That's the right attitude for this whole category. Pairing it with SkillSpector isn't overkill for skills with real permissions. Minor note: the licence file says Apache 2.0 but GitHub doesn't auto-detect it, so procurement may ask.

Licence: Apache 2.0. Stars: about 2.6k as of October 2026.

View on GitHub

5. SAST Skills

GitHub repository card for utkusen/sast-skills

What it does

Turns your coding assistant into a static code scanner. One skill maps the architecture, then 13 detection skills run in parallel for SQL injection, XSS, RCE, SSRF, IDOR, JWT flaws, missing authorisation, business logic bugs and more, before a final severity-ranked report. Works with Claude Code, Codex, OpenCode and Cursor.

Who it's for

Small dev teams and freelancers wanting a cheap first-pass review.

Our take

Simple, which counts for a lot. The business logic check is the interesting part, because traditional scanners miss those bugs. But it's one maintainer (security researcher Utku Sen), the last commit was April 2026, and you copy your project into its folder. Fine for a review, not a pipeline tool.

Licence: MIT. Stars: about 1.3k as of October 2026.

View on GitHub

Part 2: Autonomous AI pentesting

This half is different. These tools attack running systems: real requests, real exploit tools, sometimes real changes to data. Powerful, and easy to misuse, even by accident.

Read the legal section before running any of them. Point them only at systems you own, or systems you have written permission to test.

6. Strix

GitHub repository card for usestrix/strix

What it does

Teams of AI agents that run your app, probe it like an attacker and validate findings with working proofs of concept, then suggest fixes. Runs locally in Docker with your own model key, and plugs into GitHub Actions.

Who it's for

Dev teams who want security testing more often than an annual pentest.

Our take

The most popular project here by a mile, and it earns it on usability. Proof-of-concept validation cuts the false positives that make people ignore scanners. But "autonomous AI hackers" is marketing. It does the grunt work of a pentest, not the judgement. We'd run it against staging on every release and still book a human tester for anything holding customer data.

Licence: Apache 2.0. Stars: about 71k as of October 2026.

View on GitHub

7. Shannon

GitHub repository card for KeygraphHQ/shannon

What it does

An AI pentester for web apps and APIs that reads your source code, works out attack paths, then runs real exploits to prove them. Its rule: "no exploit, no report."

Who it's for

Teams testing an app whose source code they have.

Our take

That rule is the right instinct. Nobody needs another report full of maybes. Take the README seriously: it can create users, submit forms and change application state. Never point it at production. The licence is AGPL-3.0, which matters if you modify it and offer it as a service, and the advanced features sit in paid editions.

Licence: AGPL-3.0. Stars: about 49k as of October 2026.

View on GitHub

8. PentAGI

GitHub repository card for vxcontrol/pentagi

What it does

A self-hosted multi-agent pentest system. You describe a target and goal; specialised agents plan the work, run 20+ tools like nmap, Metasploit and sqlmap in an isolated Docker sandbox, remember what worked and write a report. Supports local models through Ollama or vLLM.

Who it's for

Security engineers and red teams who want everything on their own infrastructure.

Our take

Local model support is the draw for regulated Australian firms, because findings never have to leave your servers. It's a substantial install (Docker Compose, PostgreSQL, optional Neo4j), so it's a job for a specialist. Built by VXControl, a Dubai-based security company, with commercial enterprise features.

Licence: MIT. Stars: about 32k as of October 2026.

View on GitHub

9. PentestGPT

GitHub repository card for GreyDGL/PentestGPT

What it does

An agent framework that works through a pentest in stages (discovery, vulnerability identification, reporting) and can drive Claude Code or Codex to run tools. It began as research published at USENIX Security 2024.

Who it's for

Pentesters, students and CTF players who want an AI co-pilot.

Our take

The elder statesman here, created in early 2023, with peer-reviewed research behind it. That's worth something in a category full of brand-new repos. It leans towards capture-the-flag work, and the last push was July 2026. A good assistant for a skilled tester, not something to hand a non-specialist.

Licence: MIT. Stars: about 16k as of October 2026.

View on GitHub

10. HexStrike AI

GitHub repository card for 0x4m4/hexstrike-ai

What it does

An MCP server that lets AI agents run more than 150 security tools for pentesting, bug bounty and research. In plain terms, it hands an agent an entire offensive toolkit.

Who it's for

Experienced offensive security people who already know those tools.

Our take

Handle with gloves. Shortly after its 2025 release, Check Point reported criminals on underground forums discussing using it against fresh Citrix NetScaler flaws, though Check Point said it had no proof the tool was actually used in attacks. That's not a reason to ban it. It's a reason to run it only in an isolated lab, against your own systems. It's also a textbook case for MCP server security: wire this into a general-purpose agent and one prompt injection could aim it at the wrong target.

Licence: MIT. Stars: about 13k as of October 2026.

Read the Check Point report

View on GitHub

11. PentestAgent

GitHub repository card for GH05TCREW/pentestagent

What it does

An agent framework for black-box testing, bug bounty and red teaming, with single-instruction, autonomous, multi-agent "crew" and guided interactive modes, plus prebuilt attack playbooks. Works with any LiteLLM-supported model and can run tools in Docker, including a Kali image.

Who it's for

Bug bounty hunters and pentesters testing from the outside.

Our take

The interactive mode is the smartest feature, because a human stays in the loop on every step. Smaller community, rougher edges. Use the Docker option every time. Running Kali tools straight on your work laptop is how a test turns into an incident.

Licence: MIT. Stars: about 3.2k as of October 2026.

View on GitHub

What Australian businesses need to know first

Only test what you own or have written permission to test

The Part 2 tools don't know whose server they're pointed at. You do. Part 10.7 of the Criminal Code Act 1995 (Cth) covers computer offences, including unauthorised access, modification or impairment with intent to commit a serious offence (section 477.1) and unauthorised access to or modification of restricted data (section 478.1). "The AI did it" won't help you.

Get a written scope before any active test, and check your hosting and SaaS terms, since many ban testing without notice. Testing your own staging server from your Sydney CBD office is fine. Pointing Strix at a competitor's checkout page is not.

Read the Criminal Code

Map it to the Essential Eight and the new ASD Essentials

The Essential Eight is still the baseline most Australian businesses are measured against, and two controls map straight onto AI agents.

  • Restricting administrative privileges. Agents and MCP servers shouldn't run as admin or hold production credentials.
  • Application control. You decide which skills and servers are allowed, not whatever trended on GitHub this week.

On 15 October 2026 the Australian Signals Directorate also launched ASD Essentials, an evolution of the Essential Eight aimed first at government, critical infrastructure and large organisations. ASD will maintain both during the transition. Smaller businesses can keep targeting the Essential Eight. Larger ones should start a gap analysis.

View the Essential Eight

Read the ASD Essentials announcement

The Privacy Act applies to your agents too

If an agent can read customer records, it's handling personal information under the Privacy Act 1988 and the Australian Privacy Principles. The OAIC's guidance on commercially available AI products recommends against putting personal information, especially sensitive information, into publicly available AI tools. A malicious skill sending data offsite is a data breach, and if serious harm is likely, the Notifiable Data Breaches scheme applies. Pentest reports are a map of your weaknesses, so store them like one.

Australian Privacy Principles

OAIC guidance on commercial AI

Notifiable Data Breaches scheme

How to start safely

  1. Inventory first. List every agent, skill and MCP server in use. Most businesses are surprised.
  2. Scan before installing. Run new skills through SkillSpector or Cisco's scanner, and read the SKILL.md yourself. It's usually short.
  3. Sandbox everything. Scanners, audit skills and pentest agents go in a container or VM with no route to production.
  4. Least privilege. Separate accounts and read-only tokens for agents. No shared admin keys.
  5. Written authorisation for any active test, listing targets, dates and who approved it.
  6. Staging, not production, with disposable data.
  7. A human reviews every finding before anyone fixes or reports anything.
  8. Re-scan on updates. Pin versions. A clean skill can ship a malicious update next month.

FAQ

1Are open source AI security tools safe to use?

Mostly, especially those from Cloudflare, NVIDIA, Snyk and Cisco. But they're still code you didn't write, and some run other code to do their job. Sandbox them, pin versions and treat output as a lead, not a verdict.

2Can AI pentesting tools replace a human penetration tester?

No. They're fast and broad, and Strix and Shannon cut false positives by proving exploits. They're weaker on business context and judging real-world impact. Use them between human pentests, not instead of them.

3Why should a small business care about MCP server security?

MCP servers connect AI agents to your email, files, CRM and code. A poisoned one can feed the agent hidden instructions or quietly move data out. If your team uses Claude, Cursor or similar tools with plug-ins, you already have MCP servers, approved or not.

4Is it legal to run AI pentesting tools in Australia?

Yes, on systems you own or have written permission to test. Unauthorised testing can be an offence under Part 10.7 of the Criminal Code Act 1995 (Cth), whether a person or an agent sends the requests.

Want a second set of eyes on your AI agents?

We put AI agents to work inside Australian businesses, and we show the controls that make them safe to keep. That includes auditing what's already there: the skills, MCP servers, permissions and data flows your team set up, often without anyone writing it down.

Whether you're in North Sydney, Parramatta, the Northern Beaches or elsewhere in Australia, we can give you a straight answer on your AI agent and MCP setup: what to fix, what to keep and what to switch off.

Email info@ailabaustralia.com

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Article Tags

AI SecurityCyber SecurityAI AgentsMCP ServersAgent SkillsPenetration TestingOpen SourceClaude CodeAustraliaSydney

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