---
id: "CVE-2026-90866"
kind: "vulnerability"
aliases: ["CVE-2026-90866"]
title: "WS_FTP Server: path traversal lets delegated admin reach files outside scope"
severity: "critical"
cvss: 9.1
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["file-transfer", "infrastructure", "windows", "ws_ftp_server"]
not_affected_if: ["no-delegated-host-admins", "non-windows"]
published_at: "2026-10-29T16:20:04+00:00"
first_seen_at: "2026-10-29T16:26:02+00:00"
updated_at: "2026-10-29T16:27:46+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90866", "first_seen_at": "2026-10-29T16:26:02+00:00"}]
---

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

WS_FTP Server on Windows has a path traversal flaw that lets a delegated Host Administrator access locations outside their authorized scope. The sources say this could potentially enable remote code execution.

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

## How to check

- Check the installed WS_FTP Server version against the fixed versions listed in the fix section.
- Confirm whether any accounts hold the delegated Host Administrator role.

## Fix

- Move to `2024.0.7` on the 2024 line or `2025.0.4` on the 2025 line.

## Timeline

- 2026-10-29T16:26:02+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-90866

## 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 locations outside their authorized scope, potentially enabling remote code execution.

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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_