Flowise 3.1.0: HTTP Security Now Mandatory - What You Need to Know

Here at Lead AI Dot Dev, we tracked the release of Flowise 3.1.0 and identified a significant security hardening that impacts how the platform handles HTTP requests. The update introduces mandatory HTTP security validation that enables a deny list by default, preventing your workflows from making requests to potentially unsafe or internal domains.

The deny list specifically blocks access to localhost, 127.0.0.1, and other internal domain patterns. This is a deliberate breaking change designed to mitigate Server-Side Request Forgery (SSRF) attacks and similar vulnerabilities where malicious actors might abuse workflow logic to access internal infrastructure.

If you're running Flowise in production and your workflows currently make calls to internal services - database servers, internal APIs, monitoring systems, or other infrastructure on private networks - you need to act on this update immediately. The security checks are enabled by default and cannot be bypassed without configuration changes.

• HTTP security validation is now enabled by default
• Built-in deny list blocks localhost, 127.0.0.1, and similar internal addresses
• This is a breaking change for deployments using internal service calls
• Designed to prevent SSRF and related attack vectors

Builders deploying Flowise workflows that orchestrate connections between internal systems face an immediate operational challenge. The most common scenarios affected include: workflows calling internal databases, microservices on private networks, localhost development environments pushed to production, and internal monitoring or logging systems.

The security rationale is sound - SSRF vulnerabilities have been weaponized extensively against AI workflow platforms because they often sit in privileged network positions. A compromised workflow could theoretically be manipulated to probe or access internal infrastructure. Flowise is closing that attack surface proactively.

However, the enforcement mechanism creates a hard boundary. You cannot deploy a workflow that relies on internal service communication without either restructuring your architecture, whitelisting specific domains, or running an older version of Flowise. This is not a soft deprecation - it's a hard blocker.

• Internal database calls will fail unless explicitly whitelisted
• Development workflows using localhost must be rearchitected for production
• Microservices on private networks require domain allowlisting configuration
• Existing deployments will experience runtime errors on upgrade without mitigation

First, audit your current Flowise workflows immediately. Identify any nodes or flow branches that make HTTP requests to internal addresses, private IPs, or localhost. Document the specific domains and IP ranges involved. This gives you a complete inventory before deciding on upgrade timing.

Second, evaluate your architecture options. You have three realistic paths: (1) Use external-facing API endpoints instead of direct internal calls by adding a gateway or proxy layer, (2) Configure Flowise allowlists to explicitly permit the internal domains your workflows require, or (3) Defer the upgrade until you've refactored the affected workflows. There is no fourth option that maintains security and ignores the restriction.

Third, if you're whitelisting internal domains, do so surgically. Don't whitelist entire private IP ranges - specify exact domains and paths. This retains the security benefit while accommodating your legitimate internal communication needs. Document your whitelist decisions for security audits.

Thank you for listening, Lead AI Dot Dev

• Audit all workflows for internal HTTP calls within 48 hours of planning an upgrade
• Choose between refactoring, allowlisting, or deferring the upgrade - these are your only realistic options
• If whitelisting, be specific: use domain names and paths, not broad IP ranges
• Test the upgrade path in a staging environment before production deployment
• Document your security decisions for compliance and incident response purposes