CVE-2025-58640 is a medium-severity vulnerability classified under CWE-79, indicating an improper neutralization of input during web page generation, commonly known as a Cross-site Scripting (XSS) vulnerability. This vulnerability affects the MatrixAddons Document Engine product, specifically versions up to 1.2. The issue allows an attacker to inject malicious scripts that are stored persistently within the application, leading to Stored XSS attacks. Stored XSS occurs when malicious input is saved by the application and later rendered in users' browsers without proper sanitization or encoding. The CVSS 3.1 base score of 6.5 reflects a network exploitable vulnerability (AV:N) with low attack complexity (AC:L), requiring low privileges (PR:L) and user interaction (UI:R). The scope is changed (S:C), indicating that exploitation can affect resources beyond the vulnerable component. The impact affects confidentiality, integrity, and availability at a low level (C:L/I:L/A:L). This means an attacker could potentially steal session tokens, manipulate displayed content, or cause minor disruptions to service availability. No known exploits are currently reported in the wild, and no patches or fixes have been linked yet. The vulnerability arises from insufficient input validation or output encoding in the Document Engine's web page generation process, allowing malicious JavaScript code to be stored and executed in the context of users' browsers when they access affected pages. This can lead to session hijacking, defacement, or redirection to malicious sites.

For European organizations using MatrixAddons Document Engine, this vulnerability poses a significant risk to web application security and user trust. Stored XSS can be leveraged to compromise user accounts, steal sensitive data such as authentication tokens or personal information, and facilitate further attacks like phishing or malware distribution. Organizations in sectors handling sensitive or regulated data—such as finance, healthcare, and government—may face compliance violations under GDPR if personal data confidentiality is breached. The integrity of documents and displayed information could be undermined, impacting business operations and reputation. Additionally, the availability impact, though low, could disrupt document access temporarily. Since the vulnerability requires low privileges but user interaction, targeted phishing or social engineering campaigns could increase exploitation likelihood. The changed scope indicates potential for broader impact beyond the immediate application, possibly affecting integrated systems or services relying on the Document Engine.

1. Immediate mitigation should include implementing strict input validation and output encoding in the Document Engine to neutralize any potentially malicious scripts before storage or rendering. 2. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers accessing the application. 3. Conduct a thorough code review focusing on all user input points and ensure proper sanitization libraries or frameworks are used consistently. 4. Restrict privileges for users who can submit content that is rendered in web pages to minimize the risk of malicious input. 5. Monitor logs and user activity for unusual patterns indicative of attempted XSS exploitation. 6. Educate users about the risks of interacting with suspicious links or content within the application. 7. Since no patch is currently available, consider isolating or disabling vulnerable Document Engine features temporarily if feasible. 8. Plan for rapid deployment of vendor patches once released and test updates in a controlled environment before production rollout.