CVE-2024-58295 is a critical vulnerability classified under CWE-434 (Unrestricted Upload of File with Dangerous Type) affecting ElkArte Forum version 1.1.9. The flaw exists in the theme installation functionality, where authenticated administrators can upload ZIP archives containing PHP files without proper validation or sanitization. The vulnerability enables attackers to embed malicious PHP scripts within the theme package, which are then extracted and stored in the web-accessible theme directory. By accessing these uploaded PHP files via a web browser, attackers can execute arbitrary system commands on the underlying server, effectively achieving remote code execution (RCE). The CVSS 4.0 score of 8.6 reflects the high impact and ease of exploitation given that no user interaction or additional authentication beyond administrator privileges is required. The vulnerability compromises confidentiality, integrity, and availability by allowing full control over the affected system. Although no public exploits have been reported yet, the nature of the vulnerability makes it a prime target for attackers seeking to compromise forum platforms. The lack of patch links indicates that a fix may not yet be publicly available, underscoring the urgency for administrators to implement compensating controls or restrict access until a patch is released.

For European organizations using ElkArte Forum 1.1.9, this vulnerability presents a significant risk. Successful exploitation can lead to complete system compromise, allowing attackers to steal sensitive data, deface websites, deploy malware, or pivot to other internal systems. Given that forums often contain user data and community interactions, breaches could result in reputational damage and regulatory penalties under GDPR for data exposure. The requirement for administrator privileges limits the attack surface but insider threats or compromised admin accounts could be leveraged. Additionally, the ability to execute arbitrary commands can disrupt service availability, impacting business continuity. Organizations relying on ElkArte for customer or community engagement in Europe must consider the potential for targeted attacks, especially in sectors with high-value data or critical infrastructure dependencies.

1. Immediately restrict administrator access to trusted personnel and enforce strong authentication mechanisms, such as multi-factor authentication (MFA). 2. Monitor and audit administrator activities closely to detect any unauthorized theme uploads or suspicious behavior. 3. Temporarily disable the theme installation feature if possible until a patch is released. 4. Implement web application firewall (WAF) rules to detect and block attempts to upload or access suspicious PHP files within theme directories. 5. Conduct regular file integrity monitoring on theme directories to identify unauthorized file additions or modifications. 6. Segregate the web server environment to limit the impact of potential RCE, using least privilege principles for web server processes. 7. Stay informed about vendor updates and apply official patches promptly once available. 8. Educate administrators about the risks of uploading untrusted themes or files and enforce strict validation policies.