CVE-2025-47929 is a DOM-based Cross-Site Scripting (XSS) vulnerability identified in DumbDrop, a file upload application developed by DumbWareio that facilitates drag-and-drop file uploads. The vulnerability exists in versions prior to the commit db27b25372eb9071e63583d8faed2111a2b79f1b, where the application improperly neutralizes input during web page generation. Specifically, an attacker can craft a malicious file containing a payload that, when uploaded by a user, triggers the execution of arbitrary JavaScript code within the victim’s browser context. This occurs because the application fails to sanitize or encode user-supplied input correctly before rendering it in the DOM, leading to the injection of executable scripts. The vulnerability does not require authentication or privileges and can be exploited remotely by tricking a user into uploading a malicious file. The commit mentioned addresses the issue by implementing proper input validation and output encoding to prevent script injection. The CVSS 4.0 base score is 2.1, indicating a low severity primarily due to the requirement of user interaction and the limited impact on confidentiality, integrity, and availability. No known exploits are reported in the wild as of now. The vulnerability falls under CWE-79, which covers improper neutralization of input leading to XSS attacks, a common web application security flaw that can facilitate session hijacking, credential theft, or unauthorized actions within the user’s browser session.

For European organizations, the impact of this vulnerability depends on the deployment and usage of DumbDrop within their environments. If used internally or exposed on public-facing portals, the vulnerability could allow attackers to execute malicious scripts in the context of legitimate users, potentially leading to session hijacking, theft of sensitive information, or unauthorized actions performed on behalf of the user. Although the CVSS score is low, the risk is heightened in environments where users have elevated privileges or access to sensitive data through the application. Additionally, organizations subject to strict data protection regulations such as GDPR must consider the reputational and compliance risks associated with any data breaches or unauthorized access resulting from exploitation. The vulnerability’s requirement for user interaction (uploading a malicious file) limits mass exploitation but does not eliminate targeted attacks, especially social engineering campaigns aimed at employees or customers. Given the nature of file upload applications, attackers might also attempt to combine this XSS flaw with other vulnerabilities to escalate impact.

European organizations should take the following specific and practical steps to mitigate this vulnerability: 1) Immediately update DumbDrop to the fixed version containing commit db27b25372eb9071e63583d8faed2111a2b79f1b or later to ensure the vulnerability is patched. 2) Implement strict file upload controls, including validating file types, sizes, and content to prevent malicious payloads from being uploaded. 3) Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in the browser context, thereby reducing the impact of any residual XSS vulnerabilities. 4) Conduct user awareness training to reduce the likelihood of users uploading malicious files or falling victim to social engineering attacks. 5) Monitor application logs and user activity for unusual upload patterns or script execution attempts. 6) If immediate patching is not feasible, consider disabling the drag-and-drop upload feature temporarily or restricting upload capabilities to trusted users only. 7) Review and enhance input sanitization and output encoding practices across all web applications to prevent similar vulnerabilities.