CVE-2025-51741: Veal98 Echo System Vulnerable to Unauthenticated Email Flooding

Overview

CVE-2025-51741 details a vulnerability found in Veal98 Echo Open-Source Community System versions 2.2 through 2.3. This flaw allows an unauthenticated attacker to trigger the server to send email verification messages to arbitrary user email addresses. The vulnerable endpoint is located at /sendEmailCodeForResetPwd. This uncontrolled email sending can lead to a denial-of-service (DoS) condition, impacting both the server’s resources and the recipients’ inboxes.

Technical Details

The vulnerability resides in the /sendEmailCodeForResetPwd endpoint, which is intended to facilitate password resets. An attacker can make requests to this endpoint without any authentication, specifying arbitrary email addresses as the recipient. The system then proceeds to generate and send an email verification code to the specified address. By repeatedly sending requests with different email addresses or the same email address repeatedly, an attacker can flood the system with email sending requests, potentially overwhelming the server’s resources and/or overwhelming the target email address with emails.

The lack of proper rate limiting or CAPTCHA mechanisms on this endpoint makes it susceptible to automated abuse.

CVSS Analysis

While the CVE entry indicates a CVSS score of N/A, this vulnerability can be classified as a medium to high severity issue due to its potential impact. A CVSS score hasn’t been officially assigned, but a manual analysis suggests the following factors:

• Attack Vector (AV): Network (N) – The vulnerability can be exploited remotely.
• Attack Complexity (AC): Low (L) – Exploitation requires minimal skill.
• Privileges Required (PR): None (N) – No authentication is needed.
• User Interaction (UI): None (N) – No user interaction is required.
• Scope (S): Unchanged (U) – The vulnerability does not affect other resources.
• Confidentiality Impact (C): None (N) – No confidential information is exposed.
• Integrity Impact (I): None (N) – System integrity is not directly compromised.
• Availability Impact (A): High (H) – The vulnerability can cause a denial of service.

Based on these factors, a hypothetical CVSS v3 score could be around 7.5 (High) depending on the actual impact and environment. However, without an official score, this is only an estimation.

Possible Impact

The exploitation of CVE-2025-51741 can lead to several negative consequences:

• Denial of Service (DoS): The server’s email sending capabilities can be overwhelmed, preventing legitimate users from receiving important emails.
• Resource Exhaustion: The server’s CPU, memory, and network bandwidth can be consumed by processing the flood of email requests.
• Reputation Damage: The server’s IP address could be blacklisted due to sending a large volume of unsolicited emails.
• User Annoyance/Frustration: Target users will receive a large amount of unwanted password reset emails.

Mitigation or Patch Steps

The following steps can be taken to mitigate the risk of CVE-2025-51741:

1. Apply the Patch: Upgrade to a patched version of Veal98 Echo Open-Source Community System if one is available. Check the official Veal98 Echo repository for updates.
2. Implement Rate Limiting: Implement rate limiting on the /sendEmailCodeForResetPwd endpoint to restrict the number of requests that can be made from a single IP address within a given time period.
3. Implement CAPTCHA: Add a CAPTCHA challenge to the /sendEmailCodeForResetPwd endpoint to prevent automated abuse.
4. Email Queue Monitoring: Monitor the email queue for unusually high volumes of password reset requests.
5. Web Application Firewall (WAF): Deploy a WAF and configure rules to block suspicious traffic patterns targeting the vulnerable endpoint.

References

Veal98 Echo Project
Gist Detailing the Vulnerability
Veal98 Echo GitHub Repository