CriticalCVE-2025-47813

    Wing FTP Server Information Disclosure Vulnerability (CVE-2025-47813)

    Published In CISA KEV since Sources: CVE.org

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    What is affected, what to do

    loginok.html in Wing FTP Server before 7.4.4 discloses the full local installation path of the application when using a long value in the UID cookie.

    The vulnerability is being actively exploited; treat it as a priority. Update Wftpserver Wing FTP Server to version 7.4.4. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Wftpserver Wing FTP Server lt *..7.4.4
    Fixed in
    • Wftpserver Wing FTP Server 7.4.4

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    4.3

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    4.3

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: CVE.org

    62.5 %

    EPSS score

    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.

    Source: FIRST EPSS, percentile 99.19

    Show all metrics
    Severity
    Critical
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    209.86 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    actively exploitedSource: VulnCheck KEV (opens in a new tab) How we classify
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

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    4.3 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    4.3
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

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    62.5 %
    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    99.19
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    Actively exploited
    Published
    In CISA KEV since

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    CISA assessment (SSVC)
    Exploitation: active · not automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 17 March 2026
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-209

    Response and mitigation

    Why act now?

    Prioritisation rationale

    On its own this is a low-impact information disclosure. It needs only a low-privileged account, which anonymous access satisfies, and requires no user interaction over the network. It sits on KEV because the leaked installation path lets attackers reliably tune follow-on attacks against Wing FTP Server, most notably the RCE CVE-2025-47812 fixed in the same release. Exploitation likelihood is rated very high, and CISA does not flag known ransomware use. Typical targets are internet-facing file-transfer servers at mid-market firms and service providers. If you run an internet-exposed Wing FTP Server below 7.4.4, treat this as high priority: patch within 24–72 hours and include a compromise check. Internal-only instances without anonymous access can follow the regular patch cycle.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Upgrade to Wing FTP Server 7.4.4 or later on every instance (Windows, Linux, macOS). 7.4.4 fixes CVE-2025-47813 and also the critical Lua-injection RCE CVE-2025-47812, which is reached through the same web interface. Treating this as "just an info leak" understates the risk.
      • Build an inventory: Locate every Wing FTP instance exposing the web client (loginok.html, typically TCP 80/443) and the admin console (default TCP 5466). Use your CMDB or Shodan/Censys lookups against your own ranges. Internet-facing unpatched hosts go first.
      • Pull the admin console (TCP 5466) off the internet now. Allow it only from the management network or VPN.
      • Run a compromise check before patching: Path disclosure is typically a reconnaissance step for follow-on exploitation. Inspect session files (Data/_SESSION/*.lua) for injected Lua code, and review user and admin accounts for unknown entries. Preserve web and domain logs before upgrading for forensics.
      • Rotate credentials if anything looks off. This covers FTP and web-client users, admin accounts, and any service credentials stored on the host. If anonymous access is enabled, disable it, because the bug only requires a low-privileged account.

    2. Runbook step 2

      Mitigation layers

      • Network segmentation: Place Wing FTP Server in a DMZ with tight egress filtering. Block outbound internet connections from the service process (WFTPServer.exe, wftpserver) to stop payload staging if attackers chain into CVE-2025-47812.
      • WAF/reverse-proxy rule: Deny requests to /loginok.html whose UID cookie is far longer than a legitimate session ID. Example ModSecurity rule: SecRule REQUEST_COOKIES:UID "@gt 128" "id:1047813,phase:1,t:length,deny,log,msg:'CVE-2025-47813 long UID cookie'". Also block NUL/%00 bytes in login parameters (relevant to CVE-2025-47812).
      • Error-response filtering: At the reverse proxy, strip or block responses containing local path patterns such as C:\Program Files\Wing FTP Server or /opt/wftpserver.
      • IAM/least privilege: Disable anonymous login, remove unused accounts, and turn off self-registration. Run the service under a dedicated low-privilege account rather than SYSTEM/root.
      • Endpoint hardening: Minimise the service account's write access to the install directory. Enable an EDR rule that blocks or alerts on shell processes spawned by the Wing FTP process.

    3. Runbook step 3

      Detection rules

      • Web access / proxy logs: Look for requests to loginok.html carrying an oversized UID cookie. SPL sketch: index=proxy uri_path="*/loginok.html" | eval uidlen=len(mvindex(split(cookie,"UID="),1)) | where uidlen>128.
      • HTTP response content (Zeek/Suricata with TLS termination): Look for responses from the Wing FTP host that leak absolute install paths. Suricata idea: alert http $HOME_NET any -> any any (msg:"Wing FTP path disclosure"; flow:from_server; http.response_body; pcre:"/(Wing FTP Server|wftpserver)[\\\/]/i"; sid:9047813;).
      • EDR process ancestry / Sysmon EID 1: Alert when ParentImage ends in WFTPServer.exe (or the parent is wftpserver) and the child is cmd.exe, powershell.exe, certutil.exe, /bin/sh, curl or wget. This is a strong sign of follow-on CVE-2025-47812 exploitation. Sigma: selection: ParentImage|endswith: '\WFTPServer.exe' plus a shell list.
      • File integrity (Sysmon EID 11 / auditd -w <install>/Data/_SESSION -p wa): Flag session files of unusual size or containing Lua primitives such as io.popen or os.execute.
      • Wing FTP domain logs: Watch for anonymous or unknown-account logins immediately followed by error responses on loginok.html from the same source IP.

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    loginok.html in Wing FTP Server before 7.4.4 discloses the full local installation path of the application when using a long value in the UID cookie.

    Source: NVD (NIST), cvelistv5, CISA KEV Catalog, CVE.org (MITRE)

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    wftpserverWing FTP Server
    • < 7.4.4
    • 7.4.4
    wftpserverwing_ftp_server
    • < 7.4.4
    • 7.4.4

    Vendors and products

    Weakness classes (CWE)

    • CWE-209Generation of Error Message Containing Sensitive Information

      Base

      The product generates an error message that includes sensitive information about its environment, users, or associated data.

      Entry at MITRE CWE-209

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited
    Reference tagged as exploitgithub.com (opens in a new tab)PoC (publicly reported)reported, not verified—

    References & sources

    • wftpserver.comProduct
    • rcesecurity.com2025/06/what-the-null-wing-ftp-server-rce-cve-2025-47812Exploit, Third-party advisory
    • github.comMrTuxracer/advisories/blob/master/CVEs/CVE-2025-47813.txtExploit, Third-party advisory
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2025-47813government-resource, US government resource
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