CVE-2023-40044Known exploitationPublic exploitNetwork attack vector

Unauthenticated command execution via unsafe .NET deserialization

Published Sep 27, 2023 · Updated Oct 21, 2025

.NET deserialization in WS_FTP Server before 8.7.4 or 8.8.2 allows remote attackers to execute operating-system commands. The Ad Hoc Transfer IIS module passes attacker-controlled multipart field data to BinaryFormatter without restricting deserialized types. The Ad Hoc Transfer web application must be installed and reachable; successful exploitation runs commands as the IIS Network Service account.

CVSS severity10.0
Critical
EPSS probability90.15%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

.NET deserialization in WS_FTP Server before 8.7.4 or 8.8.2 allows remote attackers to execute operating-system commands. The Ad Hoc Transfer IIS module passes attacker-controlled multipart field data to BinaryFormatter without restricting deserialized types. The Ad Hoc Transfer web application must be installed and reachable; successful exploitation runs commands as the IIS Network Service account.

The record

CVE
CVE-2023-40044
Published
Sep 27, 2023
Updated
Oct 21, 2025
Vendor
Progress Software Corporation
Product
WS_FTP Server
Classifications
CWE-502, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 27, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 1, 2023Exploitation reportedRapid7-observed WS_FTP exploitation
  3. Oct 21, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=8.7.0 <8.7.4
  2. Affected versionversion=8.8.0 <8.8.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Progress Software Corporation · WS_FTP Serverversion=8.7.0 <8.7.4; version=8.8.0 <8.8.2

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
10.0Progress Software CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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