Overview
We are taking a closer look at the notable vulnerability CVE-2025-43931, a serious security weakness in the flask-boilerplate software. This vulnerability poses a significant risk to any system running versions of flask-boilerplate up to a170e7c, as it could potentially allow unauthorized attackers to take over user accounts through the password reset feature. This is a critical issue because an account takeover can lead to unauthorized access to sensitive data, system compromise, and even potential data leakage.
Vulnerability Summary
CVE ID: CVE-2025-43931
Severity: Critical (9.8 CVSS Score)
Attack Vector: Network
Privileges Required: None
User Interaction: Required
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
Flask-Boilerplate | Up to a170e7c
How the Exploit Works
The vulnerability lies within the password reset feature of the flask-boilerplate software. Due to a misconfiguration in the SERVER_NAME, the password reset depends on the Host HTTP header. An attacker can manipulate this Host header to trick the application into sending the password reset link to an email address controlled by the attacker. This allows the attacker to reset the victim’s password and subsequently take over their account.
Conceptual Example Code
Below is a conceptual example of a malicious HTTP request that could potentially exploit the vulnerability:
POST /password_reset HTTP/1.1
Host: attacker-controlled-server.com
Content-Type: application/json
{ "user_email": "victim@example.com" }In this request, the attacker manipulates the Host header to point to their own server. The flask-boilerplate system, seeing the request as legitimate, sends the password reset link to the given email address. However, due to the manipulated Host header, the reset link actually points back to the attacker-controlled server, allowing the attacker to reset the password and gain unauthorized access to the victim’s account.
Mitigation Guidance
The immediate mitigation for this vulnerability is to apply the vendor’s patch. If the patch cannot be applied immediately, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as a temporary mitigation. Ultimately, it is highly recommended to configure the SERVER_NAME properly to prevent such attacks in the future.