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VulnerabilityPublished Updated

CVE-2023-40044: Progress Software WS_FTP Server · Deserialization of Untrusted Data

Affects Progress Software WS_FTP ServerSource CVE Database V5

0

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, 14:05 UTC

CVSS 3.1 base score
10.0Critical
How severe the flaw is on the 0–10 CVSS scale.
KEV deadline
 US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
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:H

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 27 Sep 2023

  2. Weaponised: evidence found.

    1 Metasploit module

  3. Exploited in the wild: evidence found.

    Listed in CISA KEV 8 days after disclosure

  4. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. CVE ID reserved

    by Progress Software Corporation

    , 50 days before disclosure

  2. CVE published

    on cve.org

    , t = 0

  3. Added to CISA KEV (opens in a new tab)

    exploitation confirmed · ransomware use known

    , 8 days after disclosure

  4. 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 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
NuGetProgress/ws_ftp_serverpkg:nuget/Progress/ws_ftp_serverOther threatsAffected
  • =8.8.0
  • =8.7.0
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

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