EUVD-2025-30835

Comprehensive Technical Analysis of EUVD-2025-30835

1. Vulnerability Assessment and Severity Evaluation

The vulnerability described in EUVD-2025-30835 affects Flowise, a drag-and-drop user interface for building customized large language model flows. The issue allows authenticated users on the free tier to access sensitive environment variables from other tenants via the Custom JavaScript Function node. This vulnerability results in full cross-tenant data exposure, including secrets such as OpenAI API keys, AWS credentials, Supabase tokens, and Google Cloud secrets.

Severity Evaluation:

• Base Score: 9.6 (CVSS:3.1)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

The high base score of 9.6 indicates a critical vulnerability. The CVSS vector string highlights the following characteristics:

• Attack Vector (AV): Network (N)
• Attack Complexity (AC): Low (L)
• Privileges Required (PR): Low (L)
• User Interaction (UI): None (N)
• Scope (S): Changed (C)
• Confidentiality (C): High (H)
• Integrity (I): High (H)
• Availability (A): None (N)

This vulnerability is particularly severe due to its low attack complexity, the lack of user interaction required, and the high impact on confidentiality and integrity.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Authenticated Access: An attacker with a free-tier account can exploit the vulnerability.
• Custom JavaScript Function Node: The attacker can use this node to access environment variables from other tenants.

Exploitation Methods:

• Environment Variable Extraction: By crafting specific JavaScript code within the Custom JavaScript Function node, an attacker can extract sensitive environment variables.
• Data Exfiltration: Once the environment variables are accessed, the attacker can exfiltrate data to external systems, leading to unauthorized access to other services and potential data breaches.

3. Affected Systems and Software Versions

Affected Systems:

• Flowise Cloud-Hosted Version: Prior to August 2025

Software Versions:

• All versions of Flowise Cloud-Hosted prior to the August 2025 patch.

4. Recommended Mitigation Strategies

Immediate Actions:

• Patch Deployment: Ensure that all instances of Flowise Cloud-Hosted are updated to the version released in August 2025 or later.
• Access Controls: Implement strict access controls and monitoring for free-tier accounts.
• Environment Variable Management: Regularly rotate and monitor environment variables and secrets.

Long-Term Strategies:

• Code Review: Conduct thorough code reviews and security audits to identify and mitigate similar vulnerabilities.
• User Education: Educate users on the importance of securing their environment variables and the risks associated with using custom JavaScript functions.
• Incident Response Plan: Develop and maintain an incident response plan to quickly address any potential breaches.

5. Impact on European Cybersecurity Landscape

The vulnerability in Flowise poses a significant risk to the European cybersecurity landscape, particularly for organizations relying on large language models and cloud-hosted services. The exposure of sensitive environment variables can lead to widespread data breaches, unauthorized access to critical services, and potential financial losses. This underscores the need for robust security measures and continuous monitoring of cloud-hosted applications.

6. Technical Details for Security Professionals

Vulnerability Details:

• CVE ID: CVE-2025-59434
• Assigner: GitHub_M
• References: GitHub Security Advisory

Technical Analysis:

• Exploit Mechanism: The vulnerability is exploited by injecting malicious JavaScript code into the Custom JavaScript Function node, which then accesses environment variables from other tenants.
• Detection: Implement logging and monitoring for unusual access patterns and JavaScript function usage. Use intrusion detection systems (IDS) to identify and alert on suspicious activities.
• Remediation: Apply the August 2025 patch to mitigate the vulnerability. Regularly update and review access controls and environment variable management practices.

Conclusion: The vulnerability in Flowise highlights the critical importance of securing cloud-hosted applications and environment variables. Organizations must prioritize patch management, access controls, and continuous monitoring to protect against similar threats. The European cybersecurity landscape requires a proactive approach to mitigate the risks associated with such vulnerabilities.