Wing FTP Server Improper Neutralization of Null Byte or NUL Character Vulnerability (CVE-2025-47812)

Wing FTP Server contains an improper neutralization of null byte or NUL character vulnerability that can allow injection of arbitrary Lua code into user session files. This can be used to execute arbitrary system commands with the privileges of the FTP service (root or SYSTEM by default).

Published Jul 10, 2025 · Updated May 29, 2026

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Why patchRisk explained in plain English

Worst-case scenarioIf unpatched

A remote attacker, without authentication, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2025-08-04 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Software Vulnerability (CWE-158) (CWE-158) vulnerability in Wing FTP Server Wing FTP Server. In Wing FTP Server before 7.4.4. the user and admin web interfaces mishandle '\0' bytes, ultimately allowing injection of arbitrary Lua code into user session files. This can be used to execute arbitrary system commands with the privileges of the FTP service (root or SYSTEM by default). This is thus a remote code execution vulnerability that guarantees a total server compromise. This is also exploitable via anonymous FTP accounts. Exploitation requires remote network access, low attack complexity, no authentication required, and no user interaction required.

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Phishing link

→

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Malicious file

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Server compromised

Am I affected?Quick check

Probably yes if any of these apply:

●IT Security

●Running wing ftp server: v < 7.4.4

Real-world incidentsWhat we've seen

Active exploitation documented in the wild. Threat-research write-up: https://www.rcesecurity.com/2025/06/what-the-null-wing-ftp-server-rce-cve-2025-47812/

How to patch

Manual remediation steps

Apply the Vendor Patch

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog — apply the vendor's security update as soon as possible.

CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.