CVE-2009-4006: Stack-based buffer overflow in the TEA decoding algorithm in RhinoSoft Serv-U FTP server 7.0.0.1, 9.0.0.5,...

Security readout for executives and security teams

CVE-2009-4006 is a remote code execution flaw in older RhinoSoft Serv-U FTP Server versions. A specially long hexadecimal string can trigger a stack buffer overflow in TEA decoding. Organizations still running Serv-U before 9.1.0.0 should treat this as urgent legacy exposure, especially if FTP is reachable from the internet. Exposure is likely limited to legacy RhinoSoft Serv-U FTP Server deployments before 9.1.0.0. Risk is highest where the FTP service is externally reachable or accessible from untrusted networks. Prioritize remediation if any legacy Serv-U FTP server remains in use. This is an old but serious remote code execution issue affecting exposed file-transfer infrastructure, and unsupported legacy services often remain overlooked. Mitigation focus: Upgrade Serv-U FTP Server to 9.1.0.0 or later, per vendor version boundary.; Check current Serv-U release notes and vendor guidance for supported remediation paths.; Restrict FTP service exposure to trusted networks where immediate upgrade is not possible..

Prepared

Jun 28, 2026, 16:20 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.