CVE-2025-53373 is a high-severity vulnerability affecting the Natours Tour Booking API developed by ahmed-elgaml11. The vulnerability is classified under CWE-640, which pertains to weak password recovery mechanisms. Specifically, the flaw allows an attacker to hijack the password reset process by manipulating the Host header in requests to the /forgetpassword endpoint. By injecting an attacker-controlled domain into the Host header, the attacker can cause the system to send password reset links or tokens to URLs under their control, effectively enabling account takeover without requiring authentication or user interaction. This vulnerability arises from improper validation or sanitization of the Host header during the password recovery workflow. The affected versions are those prior to the commit 7401793a8d9ed0f0c250c4e0ee2815d685d7a70b, which contains the fix. The CVSS 4.0 base score is 8.9, indicating a high severity level, with an attack vector of network (AV:N), no required privileges (PR:N), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (VC:H, VI:H, VA:H). No known exploits have been reported in the wild yet. The vulnerability allows an unauthenticated attacker to fully compromise user accounts by exploiting the weak password recovery mechanism, which can lead to unauthorized access to sensitive user data and potential further exploitation within the affected system.

For European organizations using the Natours API or integrating it within their tour booking platforms, this vulnerability poses a significant risk. Successful exploitation could lead to widespread account takeovers, exposing personal data of customers, including travel plans, payment information, and personally identifiable information (PII). This could result in severe reputational damage, regulatory penalties under GDPR due to data breaches, and financial losses from fraud or remediation costs. Additionally, compromised accounts could be leveraged to conduct fraudulent bookings or disrupt service availability, impacting business operations. The lack of required authentication or user interaction makes the attack highly scalable and dangerous. Given the travel and tourism sector's importance in Europe, especially in countries with high tourism volumes, the impact could be substantial if the vulnerable API is widely deployed or used as a backend service.

Organizations should immediately verify the version of the Natours API in use and apply the patch corresponding to commit 7401793a8d9ed0f0c250c4e0ee2815d685d7a70b to remediate the vulnerability. Beyond patching, it is critical to implement strict validation and sanitization of HTTP headers, especially the Host header, to prevent injection of attacker-controlled domains. Employing allowlists for acceptable Host header values or using absolute URLs generated from trusted configuration parameters can mitigate this risk. Additionally, implementing multi-factor authentication (MFA) for account recovery processes can reduce the impact of password reset abuse. Monitoring and logging password reset requests for anomalous patterns, such as unusual Host header values or spikes in reset attempts, can help detect exploitation attempts early. Finally, organizations should conduct security reviews of all password recovery workflows to ensure they do not rely on user-controllable inputs for critical URL generation or token delivery.