CVE-2023-40044
HighExploitedPublic exploitIn 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.
Published Sep 29, 2023 · Updated Oct 21, 2025 · Also known as TR-23-0566
Key Facts
Patch immediately- CVE-2023-40044 is a high-severity vulnerability (CVSS 8.8 v3.1) affecting WS_FTP Server (Progress).
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Oct 1, 2023 and is known to be used in ransomware campaigns. Public exploit code is available.
- EPSS estimates a 90% probability of exploitation in the next 30 days.
- Fixed versions are available, including WS_FTP Server 8.7.4, WS_FTP Server 8.8.2.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
8.8
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
90%
Higher than 99.8% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings, used by ransomware
Public exploit code
Available
Proof-of-concept or weaponized module
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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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Oct 5, 2023 | Oct 26, 2023 | Known |
| Industry KEV feed | Oct 1, 2023 | Oct 26, 2023 | Known |
| CIRCL KEV | Oct 5, 2023 | Oct 26, 2023 | Known |
| ENISA EUVD | Oct 5, 2023 | n/a | Not reported |
Required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Affected Products
2 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| WS_FTP ServerProgress | >= 8.8.0 | 8.7.4 |
Patched Releases
WS_FTP Server
8.7.4, 8.8.2
Timeline
Publicly disclosed
Sep 29, 2023
Added to Industry KEV feed
Oct 1, 2023
Added to CISA KEV
Oct 5, 2023
Added to CIRCL KEV
Oct 5, 2023
Added to ENISA EUVD
Oct 5, 2023
Last updated
Oct 21, 2025
Weakness Type
- CWE-502 Deserialization of Untrusted Data
References
- advisoryhttps://attackerkb.com/topics/bn32f9sNax/cve-2023-40044
- advisoryhttps://censys.com/cve-2023-40044/
- advisoryhttps://community.progress.com/s/article/WS-FTP-Server-Critical-Vulnerability-September-2023
- advisoryhttps://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2023-40045
- advisoryVulnCheck exploitation report
FAQ
Common Questions.
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.
Affected: WS_FTP Server (Progress) versions >= 8.8.0. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Oct 1, 2023 and is known to be used in ransomware campaigns.
Yes. It was added on Oct 5, 2023 with a federal remediation due date of Oct 26, 2023.
Public exploit code is available.
Fixed versions are available, including WS_FTP Server 8.7.4, WS_FTP Server 8.8.2.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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