Why mcpsec?

MCP (Model Context Protocol) connects AI agents to external tools. Claude Desktop, Cursor, VS Code Copilot, and every major AI IDE uses it. Security is often an afterthought.

Most MCP security tools do static analysis. mcpsec connects to live servers and proves exploitation.

Real Bugs Found

More findings under responsible disclosure.

Installation

pip install mcpsec

For AI-powered features:

pip install mcpsec[ai]

Nix

nix-shell   # basic
nix-shell --arg withAll true   # all optional deps

Quick Start

Runtime Scanning

# Scan via stdio
mcpsec scan --stdio "npx @modelcontextprotocol/server-filesystem /tmp"

# Scan via HTTP with auth
mcpsec scan --http http://localhost:8080/mcp -H "Authorization: Bearer TOKEN"

# Auto-discover and scan all local servers
mcpsec scan --auto

# Enumerate attack surface
mcpsec info --stdio "python my_server.py"

Protocol Fuzzing

# Standard fuzzing (~200 cases)
mcpsec fuzz --stdio "python my_server.py"

# High intensity (~800 cases)
mcpsec fuzz --stdio "python my_server.py" --intensity high

# AI-powered payload generation
mcpsec fuzz --stdio "python my_server.py" --ai

Static Analysis

# Local source
mcpsec audit --path ./my-mcp-server

# GitHub repository
mcpsec audit --github https://github.com/user/mcp-server

# With AI validation
mcpsec audit --github https://github.com/user/mcp-server --ai

Advanced

# SQL Injection scanner with DB fingerprinting
mcpsec sql --stdio "npx @benborla29/mcp-server-mysql" --fingerprint

# Dangerous tool chain detection
mcpsec chains --stdio "npx @example/complex-server"

# Interactive exploitation REPL
mcpsec exploit --stdio "npx vulnerable-server"

# Rogue server for client-side testing
mcpsec rogue-server --port 9999 --attack all

Scanners

Fuzz Generators

22 generators organized by intensity level:

Low (~65 cases): malformed_json, protocol_violation, type_confusion, boundary_testing, unicode_attacks

Medium (~200 cases): + session_attacks, encoding_attacks, integer_boundaries

High (~800 cases): + injection_payloads, method_mutations, param_mutations, timing_attacks, header_mutations, json_edge_cases, protocol_state, protocol_state_machine, id_confusion, concurrency_attacks, regex_dos, deserialization

Insane (~1500+ cases): + resource_exhaustion, memory_exhaustion_v2

Static Analysis (149 Semgrep Rules)

24 rule files covering:

• Injection: Command injection (JS, Go, Rust, .NET, Python, Python async), SQL injection (all drivers + ORM bypass), path traversal
• Network: SSRF patterns, resource URI issues
• Secrets: AWS keys, API tokens, JWT secrets, connection strings, private keys
• MCP-Specific: Dangerous tool names, empty schemas, input reflection, missing auth
• Code Quality: Security TODOs, empty catches, TLS disabled, CORS *, ReDoS patterns

How It Works

┌─────────┐     MCP Protocol      ┌────────────┐
│ mcpsec  │ ◄──── JSON-RPC ────►  │   Target   │
│         │    (stdio / HTTP)     │   Server   │
└────┬────┘                       └────────────┘
     │
     ├── Connect & enumerate attack surface
     ├── Run 10+ security scanners  
     ├── Generate 800+ fuzz cases
     ├── Execute AI-powered payload mutations
     └── Report findings with PoC evidence

Configuration

AI Provider Setup

mcpsec setup

Supports: OpenAI, Anthropic, Google, Groq, DeepSeek, Ollama

Output Formats

# JSON
mcpsec scan --stdio "server" --output results.json

# SARIF 2.1.0 (GitHub/GitLab/Azure DevOps CI/CD)
mcpsec fuzz --stdio "server" --output results.sarif

Changelog

v2.6.1 (2026-03-20)

• CI/CD pipeline with GitHub Actions for automated testing and PyPI releases
• PR and Issue templates for better community contributions
• Nix package support via shell.nix for reproducible builds (@AbhiTheModder)
• Environment variables now properly inherited in mcp_client.py (@AbhiTheModder)

v2.6.0 (2026-03-13)

• Auto-Discovery Scanner: New --auto flag to automatically find and scan MCP servers from Claude, Cursor, VS Code, Windsurf, etc.
• Windows Unicode Fixes: Comprehensive fix for UnicodeEncodeError on Windows consoles.
• Pydantic Compatibility: Resolved AttributeError for custom metadata in scan results.

v2.5.0 (2026-03-04)

• New Scanners: code-execution, template-injection, rag-poisoning, idor, info-leak, deserialization
• Confirmation Proofs: Added mcpsec_cmd_success execution anchor for command injection
• SSRF Expansion: Support for file:// protocol and generic fetch success indicators
• Robust Parameter Handling: Automatic dummy argument generation for complex tool schemas
• Enhanced Classification: Massive reduction in false positives for blocked/sandboxed tools

v2.4.0 (2026-02-28)

• SAST Rules Expansion: 87 new Semgrep rules → 149 total across 24 rule files
• Broad patterns for command injection, path traversal, SQL injection, SSRF, deserialization
• Secrets detection: AWS keys, AI API keys, GitHub/Slack tokens, JWT secrets
• MCP-specific rules: dangerous tool names, empty schemas, error leaks, input reflection
• Code smells: security TODOs, empty catches, TLS disabled, CORS *, ReDoS patterns

v2.3.0 (2026-02-28)

• Scanner Nuclear Expansion: Command injection (138), path traversal (104), SSRF (81) payloads
• Encoding bypasses, protocol smuggling, shell-specific evasion
• 5 new fuzz generators: integer boundaries, concurrency, memory exhaustion, regex DoS, deserialization
• SDK-specific Semgrep rules for Go, Rust, Python async, .NET

v2.2.0 (2026-02-28)

• SARIF 2.1.0 Output for CI/CD integration
• CWE mapping and severity scoring
• Audit report export with --output and --format flags

v2.1.0 (2026-02-27)

• AI Exploitation Assistant: select, run, next, verdict, auto REPL commands
• Expert controls: edit, aggressive, hint for complex bypasses
• AI learns from manual call commands and response history

v2.0.3 (2026-02-26)

• MCP Repeater: Interactive REPL for manual/semi-auto finding validation
• AI payload engine with context-aware recommendations
• Exploit playbooks for SQLi, RCE, SSRF, path traversal
• Automated evidence capture and PoC generation

Contributing

See CONTRIBUTING.md for guidelines.

CI runs automatically on all PRs — linting with Ruff and cross-platform tests (Ubuntu, Windows, macOS).

Disclaimer

For authorized security testing only. Only scan servers you own or have explicit permission to test.

License

MIT