Monsta FTP - RCE (CVE-2025-34299)

CVE-2025-34299 is a critical vulnerability in Monsta FTP versions 2.11 and earlier that allows unauthenticated attackers to upload arbitrary files, potentially leading to remote code execution. Exploiting this flaw, threat actors can compromise the server by uploading malicious files from a rogue (S)FTP server, making it a significant risk for web-based file management environments.

CrowdSec has been tracking this vulnerability and its exploits since 12th of November 2025.

According to CrowdSec data, while opportunistic exploitation dominates, a portion of threat actors trying to exploit CVE-2025-34299 apply basic targeting methods such as port or service detection. This indicates emerging patterns of selective targeting. In addition, according to the CrowdSec network, attack volume against CVE-2025-34299 has dipped slightly compared to the previous week. Although still commonly targeted, the decline suggests a cooling-off period. Long-term relevance remains, but attention is waning.

Attackers exploit Monsta FTP by sending crafted POST requests to /mftp/application/api/api.php with malicious SFTP connection parameters, enabling remote file writes and potential code execution on the server.