Cross-Site Scripting stored in Alkacon OpenCMS

Posted date 30/05/2024
3 - Medium
Affected Resources

OpenCMS, version 16.


INCIBE has coordinated the publication of 2 vulnerabilities of medium severity, affecting OpenCMS version 16, an open source content manager based on Java and XML technology, which have been discovered by Miguel Segovia Gil.

These vulnerabilities have been assigned the following codes, CVSS v3.1 base score, CVSS vector and CWE vulnerability type for each vulnerability:

  • CVE- CVE-2024-5520: 6.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N | CWE-79
  • CVE- CVE-2024-5521: 6.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N | CWE-79

The Cross-Site Scripting vulnerability through the “title” field has been fixed in version 17.

However, the vendor has stated that the Cross-Site Scripting vulnerability through images in .svg format will not be fixed because filtering the JavaScript code of .svg files could bring unwanted effects. 


Two Cross-Site Scripting vulnerabilities have been discovered in Alkacon's OpenCMS affecting version 16, which could allow a user:

  • CVE-2024-5520: with sufficient privileges to create and modify web pages through the admin panel, can execute malicious JavaScript code, after inserting code in the “title” field.
  • CVE-2024-5521: having the roles of gallery editor or VFS resource manager will have the permission to upload images in the .svg format containing JavaScript code. The code will be executed the moment another user accesses the image.