CVE-2024-42699 is a Cross-Site Scripting (XSS) vulnerability identified in the Create/Modify article function of Alkacon OpenCMS version 17.0. The vulnerability arises from improper sanitization of user input in the image title sub-field within the image field, allowing a remote attacker to inject malicious JavaScript payloads. When an attacker crafts a specially designed input and injects it into the image title sub-field, the payload can execute in the context of the victim's browser when they view the affected article or content. This can lead to the theft of session cookies, user impersonation, or unauthorized actions performed on behalf of the victim. The CVSS v3.1 base score is 6.5 (medium severity), with the vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:L. This indicates that the attack can be performed remotely over the network without requiring privileges or user interaction, but the attack complexity is high. The scope is changed, meaning the vulnerability affects resources beyond the initially vulnerable component. The impact on confidentiality, integrity, and availability is low to moderate, as the attacker can potentially execute scripts that may leak data or manipulate content but does not directly lead to full system compromise. No known exploits are currently in the wild, and no patches have been published yet. The vulnerability is categorized under CWE-79, which corresponds to improper neutralization of input during web page generation leading to XSS.

For European organizations using Alkacon OpenCMS 17.0, this vulnerability poses a risk primarily to web content management and publishing workflows. Successful exploitation could allow attackers to execute arbitrary JavaScript in the browsers of users who access compromised content, potentially leading to session hijacking, credential theft, or unauthorized actions within the CMS or connected systems. This can undermine the integrity of published content and damage organizational reputation. Given that OpenCMS is often used by public sector entities, educational institutions, and enterprises for content management, the impact could extend to sensitive or critical information exposure. The vulnerability’s ability to affect confidentiality, integrity, and availability, albeit at a low to moderate level, means that attackers could manipulate displayed content or disrupt user trust. The high attack complexity reduces the likelihood of widespread automated exploitation, but targeted attacks against high-value European organizations remain a concern. The lack of user interaction requirement increases risk for automated or remote exploitation once a suitable attack vector is identified.

Organizations should immediately review and restrict the use of the image title sub-field in the Create/Modify article function within OpenCMS 17.0. Implement strict input validation and sanitization on all user-supplied data fields, especially those that accept HTML or script content. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in browsers. Monitor web application logs for suspicious input patterns targeting the image title field. Until an official patch is released, consider disabling or restricting the article creation/modification functionality to trusted users only. Conduct a thorough audit of existing content to identify and remove any injected malicious scripts. Additionally, educate content editors and administrators about the risks of injecting untrusted content. Deploy web application firewalls (WAFs) with custom rules to detect and block attempts to exploit this XSS vector. Finally, maintain up-to-date backups of CMS content to enable recovery in case of content tampering.