Overview
CVE-2025-13827 describes an arbitrary file upload vulnerability affecting the GrapesJS Builder. This vulnerability stems from a lack of restriction on the types of files that can be uploaded through the builder. If the webserver’s media folder is improperly configured, allowing execution of uploaded files, this can lead to Remote Code Execution (RCE).
Technical Details
The GrapesJS Builder, when integrated into applications (such as Mautic), typically allows users to upload media assets like images. However, CVE-2025-13827 highlights the absence of proper validation or filtering on the file types being uploaded. This means a malicious actor could potentially upload executable files (e.g., PHP, ASP, JSP, etc.) disguised as other media types or with manipulated extensions.
The key to exploiting this vulnerability lies in the server’s configuration. If the directory where uploaded files are stored (the “media folder”) is configured to execute code, the attacker can then access the uploaded executable file through a web browser, triggering its execution and potentially gaining control of the server.
CVSS Analysis
Currently, the CVE record indicates that the Severity and CVSS Score are N/A. This may be due to the specific environmental dependencies required to achieve successful exploitation (i.e., executable permissions on the upload directory). The severity will likely increase as more information is gathered and the specific attack vectors are better understood.
Factors influencing the final CVSS score could include:
- Attack Vector: Whether the exploit requires local or remote access.
- Attack Complexity: The difficulty in successfully exploiting the vulnerability.
- Privileges Required: The level of access needed to trigger the upload.
- User Interaction: Whether user interaction is required to trigger the vulnerability.
- Scope: Whether the vulnerability affects only the component or the entire system.
- Confidentiality Impact: The potential for unauthorized access to sensitive information.
- Integrity Impact: The potential for unauthorized modification of data.
- Availability Impact: The potential for disruption of service.
Possible Impact
The potential impact of CVE-2025-13827 is severe if the media folder is vulnerable to code execution. An attacker could:
- Gain Remote Code Execution (RCE): Execute arbitrary code on the server, potentially taking complete control.
- Compromise Data: Access and steal sensitive data stored on the server.
- Deface Website: Modify the website’s content to spread malware or propaganda.
- Launch Further Attacks: Use the compromised server as a launchpad for attacks against other systems.
Mitigation and Patch Steps
To mitigate the risk of CVE-2025-13827, consider the following steps:
- Restrict File Upload Types: Implement strict file type validation on the server-side to only allow permitted file types (e.g., images, documents). Use a whitelist approach rather than a blacklist. Verify file extensions, MIME types, and file headers.
- Sanitize File Names: Rename uploaded files to prevent directory traversal attacks or the use of malicious characters.
- Disable Code Execution in Upload Directory: Configure the web server to prevent the execution of scripts in the media upload directory. This is the most effective mitigation. For Apache, use
.htaccessto disable execution. For Nginx, configure the location block accordingly. - Regular Security Audits: Conduct regular security audits of your application and its dependencies to identify and address potential vulnerabilities.
- Apply Security Patches: Keep your GrapesJS Builder and any related dependencies (like Mautic) up to date with the latest security patches and updates. While a specific patch might not be available immediately for CVE-2025-13827, patching related systems is crucial.
- Content Security Policy (CSP): Implement a strong Content Security Policy to prevent the execution of untrusted scripts.
