CVE-2026-25754 is a prototype pollution vulnerability identified in the core of AdonisJS, a popular TypeScript-first web framework used for building server-side applications. The flaw exists in the multipart form-data parsing component of AdonisJS versions prior to 10.1.3 and 11.0.0-next.9. Prototype pollution occurs when an attacker can modify the prototype of a base object, thereby influencing all objects inheriting from it. In this case, the vulnerability allows a remote attacker to inject or modify properties on the Object prototype at runtime by crafting malicious multipart form-data requests. This manipulation can lead to unexpected behavior in the application, including potential privilege escalation, bypassing security controls, or data corruption. The vulnerability requires no authentication and no user interaction, making it remotely exploitable over the network. The CVSS v3.1 base score is 7.2, reflecting high severity due to the network attack vector, low attack complexity, no privileges required, and no user interaction. The impact affects confidentiality and integrity but not availability. Although no known exploits are reported in the wild, the widespread use of AdonisJS in modern web applications makes this a significant risk. The issue has been addressed in versions 10.1.3 and 11.0.0-next.9, and users are strongly advised to upgrade. The vulnerability is tracked under CWE-1321, which covers improper control of object prototype attributes.

For European organizations, this vulnerability poses a significant risk to web applications built on vulnerable versions of AdonisJS. Exploitation can lead to unauthorized modification of application logic and data, potentially exposing sensitive information or enabling further attacks such as privilege escalation or injection of malicious code. Sectors relying on Node.js frameworks for critical services—such as finance, healthcare, government, and e-commerce—may face data breaches or service integrity issues. The vulnerability’s remote exploitability without authentication increases the attack surface, especially for externally facing applications. Given the interconnected nature of European IT ecosystems, a successful attack could propagate through supply chains or interconnected services. Additionally, regulatory frameworks like GDPR impose strict data protection requirements, so exploitation leading to data leakage could result in legal and financial penalties. The absence of known exploits in the wild provides a window for proactive mitigation, but the high severity score underscores the urgency of patching.

1. Upgrade all AdonisJS core installations to version 10.1.3 or later, or 11.0.0-next.9 or later, as these versions contain the patch for this vulnerability. 2. Conduct a thorough audit of multipart form-data handling in custom application code to ensure no unsafe prototype modifications occur. 3. Implement strict input validation and sanitization on all multipart form-data inputs to prevent injection of malicious payloads. 4. Employ runtime application self-protection (RASP) or Web Application Firewalls (WAF) capable of detecting and blocking suspicious prototype pollution attempts. 5. Monitor application logs for unusual prototype manipulation patterns or errors indicative of exploitation attempts. 6. Educate development teams about prototype pollution risks and secure coding practices related to object property handling. 7. Establish a patch management process to promptly apply security updates for third-party frameworks and dependencies. 8. Consider isolating critical services and minimizing exposure of vulnerable endpoints to the public internet where feasible.