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Actively exploited

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

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).

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch nowCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 14 Jul 2025.
  • Rated Critical severity (CVSS 10.0, scored by Vendor).
  • It has been in the catalogue for 480 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

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.

Affected Versions

ProductVersions
wftpserver Wing FTP Serverbefore 7.4.4

From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for Wing FTP Server. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

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

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated critical, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 4 Aug 2025 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

Stay Ahead

More Exploited Wing FTP Server Flaws

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CVE-2025-47813Wing FTP Server Information Disclosure VulnerabilityAdded 16 Mar 2026

All 2 exploited Wing FTP Server vulnerabilities

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Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2025-47812
  3. CVE record: CVE-2025-47812
  4. FIRST EPSS
  5. wftpserver.com/serverhistory.htm
  6. wftpserver.com
  7. rcesecurity.com/2025/06/what-the-null-wing-ftp-server-rce-cve-2025-47812/
  8. vicarius.io/vsociety/posts/cve-2025-47812-mitigation-script-remote-code-execution-vulnerability-in-w
  9. vicarius.io/vsociety/posts/cve-2025-47812-detection-script-remote-code-execution-vulnerability-in-wi