CVE-2025-29287 is a critical arbitrary file upload vulnerability identified in the ueditor component integrated within MCMS version 5.4.3. This vulnerability stems from improper validation of uploaded files, classified under CWE-434 (Unrestricted Upload of File with Dangerous Type). An attacker can exploit this flaw by uploading a specially crafted file through the ueditor interface, which is typically used for rich text editing and media management within the content management system. Because the vulnerability allows arbitrary file uploads without sufficient restrictions or sanitization, an attacker can upload malicious scripts or executables that the server may subsequently execute. This leads to remote code execution (RCE), granting the attacker full control over the affected system. The CVSS 3.1 base score of 9.8 reflects the high severity, with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), and high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). There are no known public exploits in the wild yet, and no patches have been released at the time of this report. The vulnerability was reserved on March 11, 2025, and published on April 21, 2025. Given the critical nature of this vulnerability, it poses a significant risk to any organization using MCMS v5.4.3 with the vulnerable ueditor component, potentially allowing attackers to fully compromise web servers hosting the CMS and pivot further into internal networks.

European organizations using MCMS v5.4.3 with the vulnerable ueditor component face severe risks including complete system compromise through remote code execution. This can lead to data breaches involving sensitive personal and corporate data, disruption of services due to system downtime or destruction of data, and reputational damage. Critical sectors such as government, finance, healthcare, and infrastructure operators are particularly at risk due to the potential for attackers to gain persistent access and manipulate or exfiltrate critical information. The vulnerability’s ease of exploitation without authentication or user interaction increases the likelihood of automated attacks and widespread exploitation once public exploit code becomes available. Additionally, compromised systems could be leveraged as a foothold for launching further attacks within European networks or for deploying ransomware, causing cascading operational and financial impacts.

1. Immediate mitigation should include disabling or restricting file upload functionality in the ueditor component until a patch is available. 2. Implement strict server-side validation and filtering of uploaded files by enforcing file type whitelisting, checking MIME types, and validating file contents beyond just extensions. 3. Employ web application firewalls (WAFs) with custom rules to detect and block suspicious upload attempts targeting the ueditor endpoints. 4. Monitor web server logs for unusual upload activity or execution of unexpected scripts. 5. Isolate the MCMS environment from critical internal networks to limit lateral movement in case of compromise. 6. Apply the principle of least privilege to the web server process to minimize damage if exploitation occurs. 7. Once available, promptly apply official patches or updates from the MCMS vendor. 8. Conduct thorough security assessments and penetration testing focused on file upload mechanisms. 9. Educate administrators and developers about secure file upload practices and the risks of arbitrary file upload vulnerabilities.