CVE-2026-25754 identifies a prototype pollution vulnerability in the AdonisJS core framework, specifically within its multipart form-data parsing functionality. AdonisJS is a popular TypeScript-first web framework used for building server-side applications. Prototype pollution occurs when an attacker can modify the prototype of a base object, which in JavaScript affects all objects inheriting from that prototype. This can lead to unexpected behavior, security bypasses, or application logic corruption. The vulnerability allows a remote attacker to inject malicious properties into the object prototype without requiring authentication or user interaction, making it remotely exploitable over the network. The flaw affects all AdonisJS core versions prior to 10.1.3 and 11.0.0-next.9, where the multipart form-data parser does not properly sanitize or control input that modifies prototype attributes. Successful exploitation can lead to partial compromise of confidentiality and integrity by altering application state or bypassing security controls, though availability impact is not evident. The CVSS 3.1 score of 7.2 reflects the ease of exploitation (network vector, no privileges or user interaction needed) and the scope (changes can affect the entire application runtime). Although no exploits are currently known in the wild, the vulnerability poses a significant risk to applications relying on vulnerable AdonisJS versions. The issue has been addressed in versions 10.1.3 and 11.0.0-next.9 by sanitizing input and preventing prototype pollution during multipart form-data processing.

For European organizations, this vulnerability can lead to unauthorized modification of application behavior, potentially exposing sensitive data or enabling privilege escalation within web applications built on vulnerable AdonisJS versions. Given the widespread use of Node.js frameworks in Europe’s software development industry, especially in sectors like finance, healthcare, and e-commerce, exploitation could result in data breaches, compliance violations (e.g., GDPR), and reputational damage. The lack of authentication or user interaction requirements increases the risk of automated attacks. While no availability impact is indicated, integrity and confidentiality breaches can disrupt business operations and trust. Organizations running legacy or unpatched AdonisJS applications are particularly vulnerable. The threat is amplified in environments where multipart form-data is frequently processed, such as file upload features or REST APIs handling complex form submissions.

European organizations should immediately upgrade all AdonisJS core dependencies to version 10.1.3 or later (including the 11.0.0-next.9 release or newer) to apply the official patch. Conduct thorough code audits focusing on multipart form-data handling to identify and remediate any unsafe prototype manipulations. Implement strict input validation and sanitization on all user-supplied data, especially multipart form submissions. Employ runtime application self-protection (RASP) or Web Application Firewalls (WAFs) with rules targeting prototype pollution patterns to detect and block suspicious payloads. Monitor application logs for anomalous object property modifications and unusual behavior indicative of exploitation attempts. Educate development teams on secure coding practices related to prototype pollution and JavaScript object handling. Finally, maintain an up-to-date inventory of applications using AdonisJS to ensure timely patch management and vulnerability response.