---
id: "CVE-2026-90864"
kind: "vulnerability"
aliases: ["CVE-2026-90864"]
title: "WS_FTP Server: path traversal lets delegated host admin reach files outside scope"
severity: "critical"
cvss: 9.1
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["file-transfer", "runtime", "windows", "ws_ftp_server"]
not_affected_if: ["non-windows-install"]
published_at: "2026-10-29T16:20:04+00:00"
first_seen_at: "2026-10-29T16:26:01+00:00"
updated_at: "2026-10-29T16:27:48+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90864", "first_seen_at": "2026-10-29T16:26:01+00:00"}]
---

# WS_FTP Server: path traversal lets delegated host admin reach files outside scope

WS_FTP Server on Windows has a path traversal flaw that lets a delegated Host Administrator access or modify files outside their authorized scope. The sources report a CVSS score of 9.1 but do not describe the exploit path in detail.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed WS_FTP Server version in the product's admin console or installed programs list on Windows.
- Compare it against the affected ranges: prior to `2024.0.7` and prior to `2025.0.4`.

## Fix

- WS_FTP Server versions `2024.0.7` and `2025.0.4` (fixed versions named in the advisory description; move to the matching release line).

## Timeline

- 2026-10-29T16:26:01+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-90864

## From the sources

A path traversal vulnerability in Progress Software WS_FTP Server versions prior to 2024.0.7 and 2025.0.4 on Windows could allow a delegated Host Administrator to access or modify files outside their authorized scope.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_