EUVD-2025-201507

Comprehensive Technical Analysis of EUVD-2025-201507

1. Vulnerability Assessment and Severity Evaluation

The vulnerability described in EUVD-2025-201507 affects Langflow versions up to and including 1.6.9. It involves a chained vulnerability that enables account takeover and remote code execution (RCE). The chained vulnerability is composed of two primary issues:

1. Overly Permissive CORS Configuration: The Cross-Origin Resource Sharing (CORS) policy is configured with allow_origins='*' and allow_credentials=True. This allows any origin to make requests with credentials, which is a significant security risk.
2. SameSite=None Refresh Token Cookie: The refresh token cookie is configured with SameSite=None, allowing it to be sent with cross-origin requests.

The combination of these issues allows an attacker to perform cross-origin requests that include credentials, successfully call the refresh endpoint, and obtain fresh access and refresh tokens. This leads to unauthorized access to authenticated endpoints, including those with built-in code-execution functionality, resulting in full system compromise.

Severity Evaluation:

• Base Score: 9.4
• Base Score Version: 4.0
• Base Score Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

The high base score indicates a critical vulnerability with severe potential impact. The attack vector is network-based (AV:N), requires low complexity (AC:L), and does not require any special privileges (PR:N) or user interaction (UI:P). The vulnerability affects confidentiality, integrity, and availability (VC:H, VI:H, VA:H) and has a high scope change (SC:H), impacting the entire system (SI:H, SA:H).

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

1. Cross-Origin Request Forgery (CSRF): An attacker can craft a malicious webpage that performs cross-origin requests to the vulnerable Langflow instance.
2. Token Hijacking: The malicious webpage can exploit the permissive CORS configuration to include credentials in the request, allowing it to call the refresh endpoint and obtain fresh tokens.
3. Remote Code Execution (RCE): With the obtained tokens, the attacker can access authenticated endpoints and execute arbitrary code, leading to full system compromise.

Exploitation Methods:

1. Phishing: An attacker can trick users into visiting a malicious webpage that performs the cross-origin requests.
2. Malicious Advertisements: An attacker can embed the malicious code in online advertisements that are displayed on legitimate websites.
3. Compromised Websites: An attacker can compromise legitimate websites to host the malicious code.

3. Affected Systems and Software Versions

Affected Systems:

• Langflow AI Agent Workflow Platform

Affected Software Versions:

• Langflow versions up to and including 1.6.9

4. Recommended Mitigation Strategies

1. Update Software: Immediately update to a patched version of Langflow that addresses the CORS misconfiguration and refresh token cookie issues.
2. Restrict CORS Configuration: Ensure that the CORS policy is configured with specific allowed origins and does not allow credentials from untrusted origins.
3. SameSite Cookie Attribute: Configure the refresh token cookie with SameSite=Lax or SameSite=Strict to prevent it from being sent with cross-origin requests.
4. Monitor and Audit: Implement monitoring and auditing to detect and respond to any suspicious activities related to token usage and code execution.
5. User Education: Educate users about the risks of phishing and the importance of verifying the authenticity of websites and links.

5. Impact on European Cybersecurity Landscape

The vulnerability poses a significant risk to organizations using the Langflow platform, particularly those in critical sectors such as finance, healthcare, and government. The potential for account takeover and RCE can lead to data breaches, financial loss, and disruption of services. The European Union's emphasis on data protection and cybersecurity makes it imperative for organizations to address this vulnerability promptly to comply with regulations such as GDPR and NIS Directive.

6. Technical Details for Security Professionals

CORS Configuration:

• Ensure that allow_origins is set to specific trusted origins rather than '*'.
• Set allow_credentials to False unless absolutely necessary, and if necessary, ensure that only trusted origins are allowed.

SameSite Cookie Attribute:

• Configure the refresh token cookie with SameSite=Lax or SameSite=Strict to prevent it from being sent with cross-origin requests.
• Ensure that the cookie is also marked as Secure to enforce HTTPS.

Token Management:

• Implement short-lived access tokens and refresh tokens with proper expiration times.
• Use secure storage mechanisms for tokens and ensure they are not exposed in client-side code.

Code Execution Endpoints:

• Restrict access to code execution endpoints to trusted and authenticated users only.
• Implement input validation and sanitization to prevent injection attacks.

Monitoring and Logging:

• Implement comprehensive logging for all token-related activities and code execution requests.
• Use anomaly detection and alerting mechanisms to identify and respond to suspicious activities.

By addressing these technical details, security professionals can significantly reduce the risk associated with this vulnerability and enhance the overall security posture of their organizations.