CVE-2023-40044

WS_FTP Server Ad Hoc Transfer Module .NET Deserialization Vulnerability

Critical 10.0
Exploited: added to CISA KEV 5 Oct 2023
Used in ransomware campaigns

Description

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.

Key facts

Published: 27 Sep 2023
Last changed: 21 Oct 2025
Assigned by: ProgressSoftware
KEV added: 5 Oct 2023
KEV fix due: 26 Oct 2023
Used in ransomware: Yes, according to CISA
EPSS: 90.355% likely to be exploited in the next 30 days, higher than 99.803% of CVEs (scores for 15 Nov 2026)
SSVC (CISA): Exploitation: active; Automatable: yes; Technical impact: total

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

10.0CVSS 3.1, Criticalfrom the CNA (ProgressSoftware)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

What to do

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.CISA KEV required action

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

CAPEC-586 Object Injection (CNA impact statement)

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

Vendor	Product	Versions
Progress Software Corporation	WS_FTP Server	Default status: affected 8.8.0 up to but excluding 8.8.2 (affected) 8.7.0 up to but excluding 8.7.4 (affected)