Overview
CVE-2025-40834 describes a Cross-Site Scripting (XSS) vulnerability affecting the Mendix RichText widget. This vulnerability impacts versions V4.0.0 and up to, but not including, V4.6.1. An attacker could exploit this flaw to inject malicious scripts into a user’s browser, potentially leading to data theft, session hijacking, or defacement of the application.
Technical Details
The vulnerability lies in the insufficient neutralization of user-supplied input within the Mendix RichText widget. The widget fails to properly sanitize or encode user-provided data, allowing an attacker to inject arbitrary HTML and JavaScript code. When a user views content containing this malicious code, their browser executes the injected script in the context of the vulnerable Mendix application. This lack of proper input validation is the root cause of the issue.
CVSS Analysis
The Common Vulnerability Scoring System (CVSS) score for CVE-2025-40834 is 5.7, indicating a MEDIUM severity. This score reflects the potential impact of the vulnerability and the relative ease with which it can be exploited.
- CVSS Score: 5.7
- Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
- Explanation: This score suggests the attacker needs to be authenticated (low privileges) to perform the attack, requires user interaction (e.g., clicking a link), and the attack occurs over the network. The impact includes limited confidentiality and integrity, but no impact on availability.
Possible Impact
Successful exploitation of this vulnerability could have several serious consequences:
- Data Theft: An attacker could steal sensitive information, such as user credentials or personal data, from the application.
- Session Hijacking: An attacker could hijack a user’s session and gain unauthorized access to their account.
- Defacement: An attacker could deface the application, displaying misleading or malicious content to other users.
- Malware Distribution: An attacker could use the vulnerability to distribute malware to users of the application.
Mitigation and Patch Steps
To mitigate the risk posed by CVE-2025-40834, it is strongly recommended to upgrade the Mendix RichText widget to version 4.6.1 or later. This version includes a patch that addresses the insufficient input neutralization vulnerability.
- Upgrade Mendix RichText Widget: Upgrade to version 4.6.1 or a later version that contains the fix. This can be done through the Mendix Modeler.
- Input Validation: While upgrading is the primary solution, consider implementing additional input validation and sanitization measures on the server-side as a defense-in-depth strategy.
- Web Application Firewall (WAF): Employ a WAF to detect and block malicious requests targeting the vulnerability.
