langsight security-scan

Scan MCP servers for CVEs, OWASP MCP Top 10 issues, and tool poisoning

Usage

langsight security-scan [OPTIONS]

Options

Option	Default	Description
--config	auto-discovered	Path to .langsight.yaml
--json	false	Output as JSON
--ci	false	Exit code 1 on CRITICAL or HIGH findings

What it checks

CVE Scanning

Reads pyproject.toml or package.json from each server’s directory and queries the OSV API for known vulnerabilities. No API key required.

OWASP MCP Top 10

Check	Category	Severity
No authentication configured	OWASP-MCP-01	CRITICAL (SSE) / MEDIUM (stdio)
Destructive tools without auth	OWASP-MCP-02	HIGH
Unexpected schema change	OWASP-MCP-04	HIGH
Tools with no input schema	OWASP-MCP-05	MEDIUM
HTTP transport (no TLS)	OWASP-MCP-06	HIGH

Tool Poisoning Detection

Scans tool names and descriptions for:

• Prompt injection phrases (ignore previous instructions)
• Data exfiltration patterns (send all data to)
• External URLs in descriptions
• Hidden unicode characters
• Base64-encoded injection payloads

Example output

Security Scan Results  (2 servers, 4 findings)
──────────────────────────────────────────────────────────────────
Severity   Server       Category       Finding
CRITICAL   jira-mcp     CVE            CVE-2025-6514 in mcp-remote
HIGH       slack-mcp    OWASP-MCP-01   No authentication configured
HIGH       slack-mcp    OWASP-MCP-02   Tool 'delete_message' without auth
MEDIUM     postgres-mcp OWASP-MCP-05   Tool 'query' has no input schema

0/2 servers clean — 1 critical, 2 high

CI/CD integration

# Fail the build on CRITICAL or HIGH findings
langsight security-scan --ci

# In GitHub Actions
- name: MCP Security Scan
  run: langsight security-scan --ci --json > security-report.json

JSON output

[
  {
    "server_name": "jira-mcp",
    "findings_count": 2,
    "critical_count": 1,
    "highest_severity": "critical",
    "findings": [
      {
        "severity": "critical",
        "category": "CVE",
        "title": "CVE in dependency 'mcp-remote': CVE-2025-6514",
        "remediation": "Update 'mcp-remote' to a patched version."
      }
    ]
  }
]