MCP Gateway v0.3.1 Patch: XSS Mitigation & Input Validation

Vulnerability Overview MCP Gateway v0.3.1 (released on 2025-01-11) was published with a primary focus on security, XSS protection, and data validation. This release introduces comprehensive input validation, output escaping, and data sanitization to prevent XSS and injection attacks when processing data from untrusted MCP servers. Impact Scope Input Validation Framework: Comprehensive validation for all API endpoints. Output Escaping: User-controlled content is displayed in the UI with HTML escaping. Data Sanitization: Prevents XSS injection from untrusted MCP servers. Secure Defaults: Admin UI and API are disabled by default (development-only features). Automated Security Pipeline: Over 24 security tools, including CodeQL, Bandit, Trivy, and OSV-Scanner. Remediation 1. Input Validation Framework: - All endpoint validation: Tools, resources, prompts, gateway, and servers. - All non-admin API endpoint validation: Ensures data integrity. - Configurable validation rules with sensible defaults. 2. Output Escaping: - All user-controlled content is displayed with HTML escaping in the admin UI. - Protected fields: Prompt templates, tool names/comments, resource content, gateway configuration. - Ensures data is displayed as intended, without unexpected behavior. 3. Data Sanitization: - Prevents XSS injection from untrusted MCP servers. 4. Secure Defaults: - Admin UI disabled by default: - Admin API disabled by default: 5. Automated Security Pipeline: - Each PR passes 24+ automated security scans, including: - SAST: CodeQL, Bandit, multiple type checkers - Dependency Scanning: OSV-Scanner, Trivy, npm audit - Container Security: Hadolint, Dockle, Trivy - Code Quality: Multiple linters to ensure maintainability Upgrade Instructions 1. Update Package: 2. Review Security Settings: Production Deployment Checklist Disable Admin UI ( ) Disable Admin API ( ) Enable authentication for all endpoints Configure TLS/HTTPS with valid certificates Verify all MCP servers before connection Implement downstream validation in the application Set up monitoring and anomaly detection Review validation rules to adapt to your specific use case Security Considerations Upstream Validation: Verify and trust all MCP servers before connecting. Gateway Validation: Input/output validation and sanitization (this release). Downstream Validation: The application must implement its own security controls. Network Isolation: Use firewalls and network policies. Monitoring: Implement logging and anomaly alerting. Developer Security Tools Run the same 24+ security scans locally for CI/CD: Contributors Security Implementation: Input validation framework (#339, #340) and output escaping (#336) Code Quality: Achieved zero lint status across 312 issues (#338) Test Improvements: Support for UI disabled mode (#378) Version Enhancements: Semantic versioning in API (#369) UI/UX Features: Test connection tools (#181) and persistent filter state (#177) Resources Documentation: https://ibm.github.io/mcp-context-forge/ Container: ghcr.io/ibm/mcp-context-forge:v0.3.1 PyPI: mcp-contextforge-gateway Full Changelog: Compare v0.3.0...v0.3.1 Assets Assets: 2 Discussions Join Discussion: 0

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MCP Gateway v0.3.1 Patch: XSS Mitigation & Input Validation

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