CriticalVulnerabilityCVE-2026-105420updated 28 Oct 2026, 14:20 UTC

Wing FTP Server lets admins escape folder limits and write system files

An administrator account on Wing FTP Server can create user folders that break out of their allowed area and write files anywhere on the system, which can lead to full control of the server. Because the install guide uses sudo, those files

Fixed in Version 8.2.6Official source

Severity	CriticalCVSS 9.4 of 10
Being exploited?	UnclearNo reports either way yet
Fix available?	YesVersion 8.2.6 · since 28 Oct 2026
How sure is this?	Official sourceBacked by an official source

How the attack works simplified

1Admin accountAttacker already holds admin privileges
2Add user directoryScript creates a directory outside base folder
3Path escapeBase folder check is not enforced
4Write filesAttacker writes files anywhere on disk
5Code executionRuns with process owner, possibly root
ResultAttacker controls the server

What happened

Wing FTP Server does not verify that user base folders stay inside their intended base directory when admins add user directories via scripts, allowing path escape, arbitrary file writes, and remote code execution with the process owner's privileges.

Why it is dangerous: Successful exploitation can lead to remote code execution on the server with the privileges of the FTP service, potentially root if it was installed with sudo; anyone running an affected Wing FTP Server version is at risk, especially where admin accounts are not tightly controlled.

Are you affected?

You are affected if you run Wing FTP Server versions before 8.2.6, particularly installations set up with sudo that run files as root.

Wing FTP Server, versions prior to 8.2.6

What to do

Update Wing FTP Server to version 8.2.6 or later
Review existing user directories and base folders for unexpected paths or files
Restrict admin account access and audit who can run scripts that add users
Check for files owned by root in unexpected locations if the server was installed with sudo

Timeline

28 Oct 2026, 14:16 UTC
Publicly disclosed
28 Oct 2026, 14:16 UTC
Reported by NVD · NVD
28 Oct 2026, 14:20 UTC
Picked up by Zero Radar

Sources 1 report, oldest first

Official vendor, government CERT or advisory database

CVE-2026-105420NVD · 28 Oct 2026, 14:16 UTC

Technical details

ID: CVE-2026-105420
CVSS: 9.4 / 10
Disclosed: 28 Oct 2026, 14:16 UTC
On Zero Radar: 28 Oct 2026, 14:20 UTC (4 min after disclosure)
Last change: 28 Oct 2026, 14:20 UTC

The plain-language parts and the attack diagram were written by an AI model (anthropic/claude-haiku-5.5) from the sources above. Facts like versions, exploitation and dates come from the sources themselves. How Zero Radar works