CVE-2023-42659Network attack vector

Authenticated arbitrary file write via upload API

Published Nov 7, 2023 · Updated Sep 4, 2024

Unrestricted file upload in Progress WS_FTP Server before 8.7.6 and 8.8.4 allows remote authenticated users to write files via an API call. The Ad Hoc Transfer API accepts a caller-specified upload location and writes the supplied file to that operating-system path without restricting it to approved storage. Access requires an authenticated Ad Hoc Transfer account; successful exploitation can place attacker-controlled content anywhere permitted to the module's Windows service identity.

CVSS severity9.1
Critical
EPSS probability0.90%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unrestricted file upload in Progress WS_FTP Server before 8.7.6 and 8.8.4 allows remote authenticated users to write files via an API call. The Ad Hoc Transfer API accepts a caller-specified upload location and writes the supplied file to that operating-system path without restricting it to approved storage. Access requires an authenticated Ad Hoc Transfer account; successful exploitation can place attacker-controlled content anywhere permitted to the module's Windows service identity.

The record

CVE
CVE-2023-42659
Published
Nov 7, 2023
Updated
Sep 4, 2024
Vendor
Progress Software Corporation
Product
WS_FTP Server
Classifications
CWE-434, CAPEC-17, T1105
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 7, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=8.7.0 <8.7.6
  2. Affected versionversion=8.8.0 <8.8.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Progress Software Corporation · WS_FTP Serverversion=8.7.0 <8.7.6; version=8.8.0 <8.8.4

Published CVSS scores

9.1Progress Software CorporationCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L
8.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
CAPEC-17Using Malicious Files
T1105Ingress Tool Transfer

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

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Your stack

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