Executive Summary
In April 2026, security researchers identified active exploitation of a critical remote code execution (RCE) vulnerability, CVE-2025-59528, in Flowise, an open-source platform for building AI agents and large language model (LLM) workflows. This flaw, residing in the CustomMCP node, allows attackers to execute arbitrary JavaScript code without security validation, leading to potential full system compromise. Despite a patch being available since September 2025, many instances remain unpatched, exposing organizations to significant risks. (bleepingcomputer.com)
The exploitation of this vulnerability underscores the persistent threat posed by unpatched software in widely used AI development tools. Organizations leveraging Flowise must prioritize immediate updates to mitigate potential breaches and safeguard sensitive data. (bleepingcomputer.com)
Why This Matters Now
The active exploitation of CVE-2025-59528 in Flowise highlights the critical need for organizations to promptly apply security patches to prevent unauthorized access and potential data breaches. (bleepingcomputer.com)
Attack Path Analysis
An attacker exploited the CVE-2025-59528 vulnerability in Flowise's CustomMCP node to execute arbitrary JavaScript code, gaining initial access. Utilizing the elevated privileges from the Node.js runtime, the attacker escalated their access to execute system-level commands. They then moved laterally within the network, accessing other systems and services. Establishing a command and control channel, the attacker maintained persistent access. Sensitive data was exfiltrated from the compromised systems. Finally, the attacker deployed ransomware, encrypting critical files and disrupting business operations.
Kill Chain Progression
Initial Compromise
Description
The attacker exploited the CVE-2025-59528 vulnerability in Flowise's CustomMCP node to execute arbitrary JavaScript code, gaining initial access.
Related CVEs
CVE-2025-59528
CVSS 10A remote code execution vulnerability in Flowise's CustomMCP node allows unauthenticated attackers to execute arbitrary JavaScript code, leading to full system compromise.
Affected Products:
FlowiseAI Flowise – 3.0.5
Exploit Status:
exploited in the wild
MITRE ATT&CK® Techniques
Exploitation for Client Execution
Command and Scripting Interpreter
Valid Accounts
External Remote Services
Ingress Tool Transfer
Potential Compliance Exposure
Mapping incident impact across multiple compliance frameworks.
PCI DSS 4.0 – Ensure that all system components and software are protected from known vulnerabilities by installing applicable security patches
Control ID: 6.2
NYDFS 23 NYCRR 500 – Cybersecurity Policy
Control ID: 500.03
DORA – ICT Risk Management Framework
Control ID: Article 5
CISA ZTMM 2.0 – Asset Management
Control ID: 2.1
NIS2 Directive – Cybersecurity Risk Management Measures
Control ID: Article 21
Sector Implications
Industry-specific impact of the vulnerabilities, including operational, regulatory, and cloud security risks.
Computer Software/Engineering
Flowise RCE vulnerability (CVE-2025-59528) enables arbitrary JavaScript injection in AI development platforms, threatening software development workflows and custom LLM applications with command execution risks.
Information Technology/IT
Maximum severity remote code execution flaw in open-source AI platform exposes 12,000-15,000 online instances to file system access and arbitrary command execution attacks.
Financial Services
AI-powered customer support chatbots and automated workflows face critical security exposure through Flowise platform vulnerabilities, risking data exfiltration and compliance violations under regulatory frameworks.
Computer/Network Security
Active exploitation of CVSS-10 vulnerability in AI development infrastructure demonstrates critical need for enhanced egress security controls and anomaly detection in agentic AI systems.
Sources
- Max severity Flowise RCE vulnerability now exploited in attackshttps://www.bleepingcomputer.com/news/security/max-severity-flowise-rce-vulnerability-now-exploited-in-attacks/Verified
- CVE-2025-59528 Detailhttps://nvd.nist.gov/vuln/detail/CVE-2025-59528Verified
- GHSA-3gcm-f6qx-ff7phttps://github.com/FlowiseAI/Flowise/security/advisories/GHSA-3gcm-f6qx-ff7pVerified
Frequently Asked Questions
Cloud Native Security Fabric Mitigations and ControlsCNSF
Aviatrix Zero Trust CNSF is pertinent to this incident as it could have limited the attacker's ability to move laterally and exfiltrate data by enforcing strict segmentation and controlled egress policies.
Control: Cloud Native Security Fabric (CNSF)
Mitigation: While initial exploitation may still occur, Aviatrix CNSF would likely limit the attacker's ability to escalate privileges or move laterally within the network.
Control: Zero Trust Segmentation
Mitigation: Aviatrix Zero Trust Segmentation would likely limit the attacker's ability to access sensitive systems, even with elevated privileges.
Control: East-West Traffic Security
Mitigation: Aviatrix East-West Traffic Security would likely limit the attacker's ability to move laterally by enforcing strict controls on internal traffic.
Control: Multicloud Visibility & Control
Mitigation: Aviatrix Multicloud Visibility & Control would likely limit the attacker's ability to establish and maintain command and control channels.
Control: Egress Security & Policy Enforcement
Mitigation: Aviatrix Egress Security & Policy Enforcement would likely limit the attacker's ability to exfiltrate data by enforcing strict egress policies.
While initial compromise may still occur, Aviatrix CNSF would likely limit the attacker's ability to propagate ransomware across the network.
Impact at a Glance
Affected Business Functions
- AI Workflow Automation
- Customer Support Chatbots
- Knowledge-Based Assistants
Estimated downtime: 7 days
Estimated loss: $50,000
Potential exposure of sensitive customer data and intellectual property.
Recommended Actions
Key Takeaways & Next Steps
- • Implement Zero Trust Segmentation to enforce least privilege access and limit lateral movement.
- • Deploy Inline IPS (Suricata) to detect and prevent exploitation of known vulnerabilities.
- • Utilize Cloud Firewall (ACF) to control outbound traffic and prevent unauthorized data exfiltration.
- • Enhance Threat Detection & Anomaly Response capabilities to identify and respond to suspicious activities promptly.
- • Regularly update and patch systems to mitigate known vulnerabilities like CVE-2025-59528.
