CVE-2023-40044 Progress WS_FTP Server Deserialization of Untrusted Data

Exploited in the wild Critical 10.0 Published 27 Sep 2023 Updated 21 Oct 2025

A pre-authenticated attacker can execute remote commands on WS_FTP Server via a .NET deserialization flaw in the Ad Hoc Transfer module.

Exploited in the wild: Since 5 Oct 2023
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2023-40044?

CVE-2023-40044 is a critical unsafe deserialization vulnerability in Progress Software Corporation WS_FTP Server, published on 27 Sep 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-502

Which versions are affected by CVE-2023-40044?

It affects 1 product.

Products include Progress Ws Ftp Server.

How do I fix CVE-2023-40044?

No fix has been published for CVE-2023-40044 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 26 Oct 2023.

Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.

Is CVE-2023-40044 being exploited?

Yes. Attackers have exploited CVE-2023-40044 in the wild since at least 5 Oct 2023, including in ransomware campaigns.

Public exploit code: 1 Metasploit module, 1 Nuclei template and 1 proofs of concept on GitHub.

Sources

Also known as GHSA-29vf-j74g-gmfc.