Actively exploited in the wild
Progress WS_FTP Server Deserialization of Untrusted Data Vulnerability
Progress - WS_FTP Server · Listed in the CISA KEV since 2023-10-05. This indicates confirmed attacks in production environments.
Required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
CVE-2023-40044
CriticalCVSS 10.0KEVSummary
In WS_FTP Server versions prior to 8.7.4 and 8.8.2, a pre-authenticated attacker could leverage a .NET deserialization vulnerability in the Ad Hoc Transfer module to execute remote commands on the underlying WS_FTP Server operating system.
Risk Assessment
An unauthenticated attacker can execute arbitrary commands on the WS_FTP server, potentially leading to full system compromise and confidentiality breach of transferred files.
Recommendation
Upgrade WS_FTP Server to version 8.7.4 or 8.8.2 (or later). Restrict access to the Ad Hoc Transfer module to trusted users only.
Other vulnerabilities in WS_FTP Server
See all- CVE-2026-90869High
A remote attacker who knows a valid account's enrolled SSH public key can terminate the shared SSH service in Progress Software WS_FTP Server versions prior to 2024.0.7 and 2025.0.4 on Windows.
- CVE-2026-90867High
Improper access control in the Web Admin console of Progress Software WS_FTP Server versions prior to 2024.0.7 and 2025.0.4 on Windows could expose administrative functionality to remote authentication attempts.
- CVE-2026-90862Medium
Improper authentication in the Web Transfer Module of Progress Software WS_FTP Server versions prior to 2024.0.7 and 2025.0.4 on Windows could allow an attacker with a user's password to access certain files associated with that account without satisfying multi-factor authentication requirements.
- CVE-2026-90861Medium
Progress Software WS_FTP Server versions prior to 2024.0.7 and 2025.0.4 on Windows may expose a user's password in clear text to another administrator, who could use it to gain broader administrative access to the server.
- CVE-2026-84296Medium
Multi-Factor Authentication Bypass vulnerability in SSH component in Progress Software WS_FTP Server versions prior to 2024.0.6, and 2025.0.3 on Windows allows authenticated users to bypass MFA requirements through improper association of authentication factors between accounts.
- CVE-2026-84294High
Improper limitation of pathname in the Ad Hoc Transfer component of Progress Software WS_FTP Server versions prior to 2024.0.6 and 2025.0.3 on Windows could allow an authenticated user to access files outside intended directories.
- CVE-1999-0362Medium
WS_FTP server is vulnerable to a remote denial of service (DoS) attack through the cwd command.
Original NVD description (English source)
In WS_FTP Server versions prior to 8.7.4 and 8.8.2, a pre-authenticated attacker could leverage a .NET deserialization vulnerability in the Ad Hoc Transfer module to execute remote commands on the underlying WS_FTP Server operating system.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS