Quantum Secular Labs / Blog / Advisories

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

CVE-2025-47812 is rated critical with a CVSS v3.1 base score of 10.0 and affects Wing FTP Server Wing FTP Server. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available. CISA added it to its Known Exploited Vulnerabilities catalog on 2025-07-14, which means exploitation in the wild has been observed.

Vulnerability description

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.

Severity breakdown

CVSS v3.1 10.0: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: None. No account or prior access is needed.
  • User interaction: None. No action from any user is needed.
  • Scope: Changed. Impact reaches beyond the vulnerable component to other resources.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-158: Improper Neutralization of Null Byte or NUL Character

The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes NUL characters or null bytes when they are sent to a downstream component.

Affected products

  • Wftpserver Wing FTP Server: before 7.4.4

References