CVE-2025-52239 is an arbitrary file upload vulnerability identified in ZKEACMS version 4.1. This vulnerability allows an attacker to upload crafted files to the web server hosting the CMS, which can then be executed to run arbitrary code. The vulnerability arises because the application does not properly validate or restrict the types of files that can be uploaded, nor does it sufficiently sanitize the file content or file names. Exploiting this flaw, an attacker could upload malicious scripts or executables, leading to remote code execution (RCE) on the server. This could allow the attacker to gain unauthorized access, manipulate website content, steal sensitive data, or pivot further into the internal network. Although no known exploits are currently reported in the wild, the vulnerability is publicly disclosed and could be targeted by threat actors once exploit code becomes available. The lack of a CVSS score indicates that the vulnerability is newly published and not yet fully assessed. The absence of patch links suggests that a fix may not yet be available, increasing the urgency for organizations to implement mitigations. Since ZKEACMS is a content management system, it is likely used by organizations to manage web content, making this vulnerability a significant risk for website integrity and backend infrastructure security.

For European organizations using ZKEACMS v4.1, this vulnerability poses a critical risk. Successful exploitation could lead to unauthorized remote code execution, resulting in full compromise of the web server. This could lead to data breaches involving personal data protected under GDPR, reputational damage, service disruption, and potential regulatory penalties. Attackers could deface websites, inject malicious content to target visitors, or use the compromised server as a foothold for lateral movement within corporate networks. Given the importance of web presence and online services for European businesses, especially in sectors like finance, healthcare, and government, the impact could be severe. Additionally, if exploited in critical infrastructure or public sector websites, it could disrupt essential services or erode public trust. The lack of known exploits currently may provide a window for proactive defense, but the public disclosure increases the risk of imminent exploitation attempts.

European organizations should immediately audit their use of ZKEACMS to identify any instances of version 4.1. Until an official patch is released, organizations should implement strict file upload controls, including disabling file uploads where possible, or restricting allowed file types to safe formats only (e.g., images with strict MIME type and content validation). Employ web application firewalls (WAFs) with custom rules to detect and block suspicious file upload attempts and execution of unauthorized scripts. Conduct thorough monitoring of web server logs for unusual activity indicative of exploitation attempts. Isolate the CMS server from critical internal networks to limit lateral movement if compromised. Organizations should also prepare to apply patches promptly once available and consider engaging with the vendor or community for updates. Regular backups of website content and configurations should be maintained to enable rapid recovery. Finally, user privileges should be minimized, ensuring that only authorized personnel can upload files or modify CMS configurations.