CVE-2025-59434 Overview
CVE-2025-59434 is a critical cross-tenant information disclosure vulnerability in Flowise Cloud, a drag and drop user interface for building customized large language model flows. Prior to August 2025, an authenticated vulnerability in Flowise Cloud allowed any user on the free tier to access sensitive environment variables from other tenants via the Custom JavaScript Function node. This includes secrets such as OpenAI API keys, AWS credentials, Supabase tokens, and Google Cloud secrets — resulting in a full cross-tenant data exposure.
Critical Impact
Attackers with a free-tier account can exfiltrate sensitive credentials and API keys belonging to other tenants, potentially compromising connected cloud services, AI/ML pipelines, and downstream integrations.
Affected Products
- Flowise Cloud (Cloud-Hosted) prior to August 2025
- Flowise Cloud Free Tier accounts with Custom JavaScript Function node access
Discovery Timeline
- 2025-09-22 - CVE-2025-59434 published to NVD
- 2025-09-22 - Last updated in NVD database
Technical Details for CVE-2025-59434
Vulnerability Analysis
This vulnerability is classified under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor). The flaw exists within the Custom JavaScript Function node feature in Flowise Cloud, which allows users to write and execute custom JavaScript code within their LLM workflows. Due to insufficient tenant isolation controls, authenticated users can access environment variables that belong to other tenants in the multi-tenant cloud environment.
The vulnerability enables attackers to retrieve highly sensitive credentials including OpenAI API keys, AWS access credentials, Supabase tokens, and Google Cloud secrets. Since these secrets are commonly used to authenticate with external services, a successful exploit could lead to unauthorized access to third-party cloud resources, data exfiltration, and financial abuse of API quotas belonging to other organizations.
Root Cause
The root cause of CVE-2025-59434 is improper access control in the Custom JavaScript Function node execution environment. The multi-tenant architecture failed to properly isolate environment variable access between tenants. When users executed custom JavaScript functions, the execution context had access to a shared environment variable namespace rather than tenant-scoped variables, allowing cross-tenant data retrieval.
Attack Vector
The attack is network-based and requires low-privilege authentication (a free-tier Flowise Cloud account). An attacker would create or modify a workflow containing a Custom JavaScript Function node, then craft JavaScript code designed to enumerate and exfiltrate environment variables. Since no user interaction is required and the vulnerability affects the confidentiality and integrity of other tenants' data, the scope is changed — meaning the vulnerable component impacts resources beyond its security scope.
The exploitation mechanism involves accessing the process environment or a similarly exposed variable store within the JavaScript execution context to retrieve secrets belonging to other Flowise Cloud tenants.
Detection Methods for CVE-2025-59434
Indicators of Compromise
- Unusual JavaScript function executions that reference process.env, environment, or similar variable access patterns
- Unexpected API calls or authentication attempts from leaked credentials against external services (OpenAI, AWS, Google Cloud, Supabase)
- Anomalous workflow creation or modification activity from free-tier accounts
- Logs showing environment variable enumeration attempts within Custom JavaScript Function nodes
Detection Strategies
- Monitor Flowise Cloud audit logs for Custom JavaScript Function node executions with suspicious code patterns
- Implement alerting on external service authentication failures that may indicate credential testing
- Review workflow modification history for newly created functions containing environment access code
- Correlate sudden API usage spikes in connected services with Flowise activity logs
Monitoring Recommendations
- Enable detailed logging for all Custom JavaScript Function node executions
- Set up alerts for credential rotation or unauthorized access attempts in connected cloud services (AWS CloudTrail, Google Cloud Audit Logs)
- Monitor for unusual data access patterns or quota consumption in integrated AI/ML services
- Implement real-time scanning of JavaScript code submitted to Custom Function nodes
How to Mitigate CVE-2025-59434
Immediate Actions Required
- Upgrade to the August 2025 Cloud-Hosted Flowise release or later immediately
- Rotate all API keys, credentials, and tokens that were stored as environment variables in Flowise Cloud
- Review audit logs to identify any suspicious Custom JavaScript Function node activity prior to patching
- Verify that connected third-party services (OpenAI, AWS, Google Cloud, Supabase) have not been accessed by unauthorized parties
Patch Information
This issue has been patched in the August 2025 Cloud-Hosted Flowise release. Users of Flowise Cloud should ensure they are using the patched version. For additional details on the security fix, refer to the GitHub Security Advisory.
Workarounds
- Avoid storing sensitive credentials directly as environment variables until the patch is applied
- Temporarily disable Custom JavaScript Function nodes if business requirements allow
- Implement additional secret management solutions with tenant-scoped access controls
- Consider using self-hosted Flowise deployments with proper network isolation for sensitive workloads
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
