CVE-2025-47787 is a critical vulnerability affecting emlog, an open source website building system, specifically versions prior to 2.5.10. The vulnerability resides in the store.php component responsible for handling plugin uploads via ZIP files. The core issue is an insufficient validation mechanism for the contents of remotely downloaded ZIP plugin files, classified under CWE-434 (Unrestricted Upload of File with Dangerous Type). This flaw allows an attacker to upload malicious files disguised within plugin ZIP archives, leading to arbitrary code execution on the vulnerable server without requiring any authentication or user interaction. The CVSS 4.0 score of 8.9 reflects the high severity, with network attack vector, low attack complexity, no privileges or user interaction needed, and high impact on confidentiality, integrity, and availability. The vulnerability enables attackers to fully compromise the affected system, potentially gaining control over the website, stealing sensitive data, defacing content, or using the server as a pivot point for further attacks. Although no known exploits are currently reported in the wild, the ease of exploitation and the critical impact make this a significant threat. The issue was addressed in emlog version 2.5.10 by implementing proper validation and sanitization of uploaded plugin ZIP files to prevent dangerous file types from being processed.

For European organizations using emlog as their website building platform, this vulnerability poses a substantial risk. Successful exploitation can lead to full system compromise, resulting in data breaches, loss of customer trust, website defacement, and potential regulatory penalties under GDPR due to unauthorized access or data leakage. The ability to execute arbitrary code remotely without authentication means attackers can rapidly exploit vulnerable systems at scale. This is particularly concerning for small and medium enterprises (SMEs) and public sector entities that may rely on emlog for their web presence but lack robust cybersecurity defenses. Additionally, compromised websites can be leveraged to distribute malware or conduct phishing campaigns targeting European users, amplifying the threat beyond the initial victim. The high impact on confidentiality, integrity, and availability can disrupt business operations and damage reputations.

European organizations should immediately verify their emlog version and upgrade to version 2.5.10 or later to apply the official patch. Beyond patching, organizations should implement strict input validation and file type restrictions on all upload functionalities, including plugins, to prevent malicious files from being accepted. Employing web application firewalls (WAFs) with rules to detect and block suspicious ZIP file uploads can provide an additional defensive layer. Regularly auditing and monitoring web server logs for unusual upload activity or execution patterns can help detect exploitation attempts early. Organizations should also enforce the principle of least privilege on web server processes to limit the impact of a successful exploit. Backup procedures should be reviewed to ensure rapid recovery in case of compromise. Finally, educating developers and administrators about secure plugin management and the risks of third-party components is critical to prevent similar vulnerabilities.