---
id: CVE-2026-90869
title: >-
  Pre-Authentication SSH Denial of Service via Malformed Public-Key Signature in
  Progress WS_FTP Server
summary: >-
  A remote attacker who knows a valid account's enrolled SSH public key can
  terminate the shared SSH service in Progress Software WS_FTP Server versions
  prior to 2024.0.7 and 2025.0.4 on Windows.
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-125
  - CWE-20
vendor: Progress Software
product: WS_FTP Server
affected:
  - ws_ftp_server < 2024.0.7
  - ws_ftp_server < 2025.0.4
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-30T17:14:25.359940Z'
published: '2026-10-29'
updated: '2026-10-30'
sourceUpdated: '2026-10-30T17:14:35.864Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-90869'
references:
  - url: >-
      https://progress.lightning.force.com/lightning/r/Knowledge__kav/ka7Pb000001vl86IAA/view
tags:
  - cve.org
epss: 0.00356
epssPercentile: 0.29567
ingestedAt: '2026-11-05T16:24:31.148Z'
---

## Overview

A remote attacker who knows a valid account's enrolled SSH public key can terminate the shared SSH service in Progress Software WS_FTP Server versions prior to 2024.0.7 and 2025.0.4 on Windows.

## Affected

- `ws_ftp_server < 2024.0.7`
- `ws_ftp_server < 2025.0.4`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

### Workarounds

Restrict network access to the SSH/SFTP service to trusted clients and disable SSH/SFTP access if it is not required. Contact Progress Software Technical Support for guidance on available mitigations.