Description

SolarWinds has issued patches for three high-severity vulnerabilities in its Serv-U managed file transfer and FTP platform, each rated CVSS 9.1. These flaws, which exist in all Serv-U releases prior to version 15.5.3, can permit remote code execution (RCE) if an attacker already holds authenticated administrative access. The company strongly urges customers to upgrade immediately, as older builds remain exposed. The first issue, CVE-2025-40547, is tied to a logic error that becomes exploitable once an attacker obtains admin-level control inside the Serv-U environment. SolarWinds notes that while the overall rating is Critical, Windows installations may face comparatively reduced risk due to common privilege-separation practices, where services often run with less-privileged accounts. A second vulnerability, CVE-2025-40548, arises from missing validation in Serv-U’s authorization mechanisms. The flaw similarly requires administrative access but could allow a malicious actor to execute arbitrary code if abused. The third vulnerability, CVE-2025-40549, involves a bypass of directory path restrictions. By taking advantage of this weakness, a threat actor with admin rights could escape permitted directory boundaries and execute code in unauthorized file locations. SolarWinds again highlights that Windows systems may experience lower impact because of differences in how the operating system enforces home directory and path handling rules. All three vulnerabilities were responsibly disclosed by security researcher Maurice Moss. Organizations running Serv-U FTP Server or Serv-U Managed File Transfer Server should verify their deployments and ensure they have upgraded to Serv-U 15.5.3, where these issues have been fully remediated. Any outdated versions should be replaced or updated without delay to minimize security exposure.