CVE-2025-7783 is a critical security vulnerability identified in the popular form-data JavaScript library, specifically in versions prior to 2.5.4, between 3.0.0 and 3.0.3, and between 4.0.0 and 4.0.3. The root cause is the use of insufficiently random values (classified under CWE-330) during the processing of form data, which leads to HTTP Parameter Pollution (HPP). HPP is an attack technique where an attacker manipulates or injects multiple HTTP parameters with the same name, potentially altering application logic or bypassing security controls. The vulnerability resides in the program file lib/form_data.js, which is responsible for parsing and handling form data in HTTP requests. The CVSS 4.0 score of 9.4 reflects a critical severity level, with the vector indicating network attack vector (AV:N), high attack complexity (AC:H), no privileges or user interaction required (PR:N/UI:N), but with high impact on confidentiality (VC:H), integrity (VI:H), and availability (VA:N). The scope is high (S: H), meaning the vulnerability can affect resources beyond the initially vulnerable component. Although no exploits have been observed in the wild yet, the potential for attackers to manipulate HTTP parameters remotely without authentication makes this a significant threat. This vulnerability can lead to unauthorized data access, injection of malicious parameters, session manipulation, or bypassing of input validation mechanisms, potentially compromising web applications and APIs that rely on the vulnerable form-data library. The vulnerability affects a wide range of versions, indicating multiple release branches are impacted, which complicates patch management. The lack of available patches at the time of publication necessitates immediate risk mitigation through alternative controls.

For European organizations, the impact of CVE-2025-7783 is substantial. Many enterprises and public sector entities in Europe utilize web applications and APIs that depend on the form-data library for handling HTTP form submissions. Exploitation of this vulnerability could allow attackers to perform HTTP Parameter Pollution attacks, leading to unauthorized data manipulation, session hijacking, or bypassing of security controls. This threatens the confidentiality and integrity of sensitive data, including personal data protected under GDPR, potentially resulting in regulatory fines and reputational damage. Critical infrastructure sectors such as finance, healthcare, and government services are particularly at risk due to their reliance on web-based services and APIs. The high attack complexity reduces the likelihood of widespread automated exploitation, but targeted attacks against high-value European organizations remain a serious concern. The vulnerability's ability to affect availability is limited, but indirect denial of service or application logic disruption could occur. Overall, the threat could undermine trust in digital services and lead to significant operational and compliance challenges.

To mitigate CVE-2025-7783, European organizations should prioritize upgrading the form-data library to versions later than 2.5.4, 3.0.3, or 4.0.3 as soon as patches become available. Until official patches are released, organizations should implement strict input validation and sanitization on all HTTP parameters to detect and reject duplicated or suspicious parameter names. Web application firewalls (WAFs) can be configured to detect and block HTTP Parameter Pollution attempts by inspecting incoming requests for anomalous parameter patterns. Developers should review application logic to ensure it does not rely on ambiguous parameter handling and enforce explicit parameter parsing strategies. Security teams should conduct thorough code audits and penetration testing focused on parameter handling vulnerabilities. Monitoring and logging of HTTP requests should be enhanced to detect potential exploitation attempts. Additionally, organizations should educate developers and operations teams about the risks of insufficient randomness in security-critical components and promote secure coding practices. Finally, maintaining an inventory of software dependencies and their versions will facilitate rapid response to such vulnerabilities.