---
id: "CVE-2026-90871"
kind: "vulnerability"
aliases: ["CVE-2026-90871"]
title: "WS_FTP Server: path traversal lets unauthenticated users reach files outside directory"
severity: "medium"
cvss: 5.3
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["file-transfer", "runtime", "windows", "ws_ftp_server"]
not_affected_if: ["non-windows-hosts", "patched-versions"]
published_at: "2026-10-29T16:20:05+00:00"
first_seen_at: "2026-10-29T16:26:03+00:00"
updated_at: "2026-10-29T16:31:46+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90871", "first_seen_at": "2026-10-29T16:26:03+00:00"}]
---

# WS_FTP Server: path traversal lets unauthenticated users reach files outside directory

WS_FTP Server on Windows fails to keep file paths inside their intended directory. An unauthenticated attacker can affect files outside that directory.

_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 below.
- Confirm whether the server runs on Windows.

## Fix

- WS_FTP Server `2024.0.7` or later on the 2024 line
- WS_FTP Server `2025.0.4` or later on the 2025 line

## Timeline

- 2026-10-29T16:26:03+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-90871

## From the sources

Improper limitation of a pathname to a restricted directory in Progress Software WS_FTP Server versions prior to 2024.0.7 and 2025.0.4 on Windows could allow an unauthenticated attacker to affect files outside the intended directory.

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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_