How severe is CVE-2023-40044?

CVE-2023-40044 has a CVSS score of 10/10, rated CRITICAL. Immediate patching is strongly recommended.

Which products are affected by CVE-2023-40044?

CVE-2023-40044 affects the following products: progress ws ftp server.

How do I patch CVE-2023-40044?

Apply the progress ws ftp server security patch or hotfix for CVE-2023-40044 on the affected version, following the vendor advisory for your exact build.

How do I detect CVE-2023-40044 across my infrastructure?

Inventory every progress ws ftp server deployment and check each version against the affected-products list above.

How do I mitigate CVE-2023-40044 if there is no patch (or I can't update yet)?

Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.

Is CVE-2023-40044 actively exploited in the wild?

Yes. There are 5 known exploit references for CVE-2023-40044, including 5 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2023-40044?

CVE-2023-40044 has an EPSS (Exploit Prediction Scoring System) score of 90.4%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2023-40044 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2023-40044 (Progress WS_FTP Server Deserialization of Untrusted Data Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2023-10-05. CISA required all US federal civilian agencies to remediate this vulnerability by 2023-10-26. The required action was: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. This CVE has been used in known ransomware campaigns. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2023-40044?

CVE-2023-40044 is classified as Deserialization of Untrusted Data (CWE-502). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Which products and versions are affected by CVE-2023-40044?

CVE-2023-40044 affects progress ws ftp server. Check the affected-products list on this page against your deployed version to confirm exposure.

Is there exploit tooling available for CVE-2023-40044?

A Nuclei detection template exists for CVE-2023-40044, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2023-40044 published, and has it been updated?

CVE-2023-40044 was published on September 27, 2023 and was last updated on June 17, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

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CISA KEV · ACTIVELY EXPLOITED

CRITICAL severity

CVE-2023-40044 — Ws Ftp Server

CRITICAL

CVE-2023-40044 is a critical-severity (CVSS 10) Deserialization of Untrusted Data vulnerability in progress ws ftp server. It is in CISA's Known Exploited Vulnerabilities catalog (added 2023-10-05) and has been used in ransomware campaigns — treat it as actively exploited and patch now. A fix is available — see the affected versions and patch details below.

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…

Published

Sep 27, 2023

Updated

Jun 17, 2026

Affected

1 product

Patched

See advisory

Exploits

5 known

Exploitation data as of Oct 22, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2023-10-05 — including use in ransomware campaigns. Federal agencies were required to remediate by 2023-10-26.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2023-40044.

EPSS Exploitation Probability

via FIRST.org ↗

90.4%probability of exploitation in next 30 days

Very High Risk-0.20%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2023-40044 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).

Where this sits among everything scored

Of 394,803 CVEs with a current EPSS score, this one falls in the ≥ 90% band (highlighted). Counts from FIRST.org, log-scaled.

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.

Affected Products

1 product · 2 configurations

Application

ws ftp serverprogress

≥ 8.8 && < 8.8.2

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.