CVE-2023-40044: Progress Software WS_FTP Server · Deserialization of Untrusted Data
Affects Progress Software WS_FTP ServerSource CVE Database V5
Exploited in the wild · used in ransomware campaigns · KEV due 26 Oct 2023 · public exploit available (Metasploit) · 90% EPSS : apply the vendor's fix or mitigations to Progress Software WS_FTP Server now.
Data as of 26 Oct 2026, 06:26 UTC
- KEV deadline
- US federal agencies must patch by this date; a sensible deadline for everyone else.
- Ransomware
- Used in ransomware campaigns
- EPSS
- 90.3% chance of exploitation in 30 days – higher than 99% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HExploitation evidence
t = 0 is the CVE’s publication on cve.org
Disclosed: evidence found.
CVE published 27 Sep 2023
Detectable: evidence found.
Weaponised: evidence found.
Exploited in the wildExploited: evidence found.
Listed in CISA KEV 8 days after disclosure
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
Timeline
CVE ID reserved
by ProgressSoftware
, 50 days before disclosure
CVE published
on cve.org
, t = 0
Added to CISA KEV (opens in a new tab)
exploitation confirmed · ransomware use known
, 8 days after disclosure
KEV remediation due
US federal deadline
, 29 days after disclosure
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.
What to do
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
NuGetProgress/ws_ftp_serverpkg:nuget/Progress/ws_ftp_serverOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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.
References
- progress.com/ws_ftp (opens in a new tab)
- community.progress.com/s/article/WS-FTP-Server-Critical-Vulnerability-September-2023 (opens in a new tab)
- theregister.com/2023/10/02/ws_ftp_update/ (opens in a new tab)
- rapid7.com/blog/post/2023/09/29/etr-critical-vulnerabilities-in-ws_ftp-server/ (opens in a new tab)
- attackerkb.com/topics/bn32f9sNax/cve-2023-40044 (opens in a new tab)
- censys.com/cve-2023-40044/ (opens in a new tab)
- assetnote.io/resources/research/rce-in-progress-ws-ftp-ad-hoc-via-iis-http-modules-cve-2023-40044 (opens in a new tab)
- packetstormsecurity.com/files/174917/Progress-Software-WS_FTP-Unauthenticated-Remote-Code-Execution.html (opens in a new tab)
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-40044 (opens in a new tab)