CVE-2025-47813 is an information disclosure vulnerability in Wing FTP Server Wing FTP Server. CISA added it to the Known Exploited Vulnerabilities catalogue on 16 March 2026, which means attackers have used it in real attacks. Wing FTP Server contains a generation of error message containing sensitive information vulnerability when using a long value in the UID cookie.
How this vulnerability behaves
CVE-2025-47813 is an information disclosure flaw in Wing FTP Server, triggered when the product processes an unusually long UID cookie value and generates an error message that can reveal sensitive information. In practice, the danger is not just that one error leaks data, but that disclosed details can help an attacker understand the application’s internal state and pursue follow-on abuse.
Information disclosure issues often look modest compared with remote code execution, yet they can still weaken a system materially. They can expose session-adjacent data, internal paths, product behaviour, or other clues that reduce the effort needed for later exploitation, especially when the exposed service is internet-facing.
Why this kind of disclosure matters in file transfer software
FTP servers are commonly exposed to external users, partners, and automation, so even a narrow disclosure bug deserves attention. File transfer platforms also tend to sit near sensitive data flows, which means a leak from the application layer can become a stepping stone into broader operational or identity exposure if it reveals account structure, request handling, or other implementation details.
The practical problem is that attackers do not need full compromise to benefit. A disclosure flaw can improve reconnaissance, make targeted exploitation more reliable, and provide context for chaining into credential abuse, session attacks, or a deeper server compromise if another weakness is present.
How organisations assess exposure and confirm impact
Exposure checks should start with an accurate inventory of where Wing FTP Server is deployed, who administers it, and whether any instance is reachable from the internet or from partner networks. That inventory should then be compared with the vendor advisory and authoritative vulnerability records such as the NIST National Vulnerability Database and the CVE Program entry for the exact identifier.
Because this issue was added to CISA’s KEV catalogue, organisations should treat it as actively exploited and prioritise confirmation of exposure rather than waiting for routine maintenance windows. In addition to version checks, teams should review whether logs show requests using abnormal UID cookie lengths, repeated server errors, or other signs that the vulnerable code path has already been touched.
Remediation, monitoring, and post-exposure review
The preferred response is to apply the vendor’s fix as soon as operationally possible and verify the result after deployment. If patching is delayed, reduce exposure by restricting who can reach the service, tightening error handling and logging visibility, and limiting unnecessary internet access until the vulnerable instance is corrected. For patch planning and prioritisation discipline, the Vulnerability Management Guide is a useful companion reference.
After remediation, review access logs, application logs, and adjacent authentication activity for signs that the disclosure may have been used as part of a broader intrusion attempt. If the system exposed sensitive internal details, assess whether any credentials, sessions, or administrative secrets may also have been observed or reused elsewhere, then rotate them where there is credible indication of exposure.
Risk and Threat Considerations
Information disclosure bugs are often attractive to attackers because they can be low-noise, easy to trigger, and useful for reconnaissance before a larger intrusion. In a network-facing transfer platform, even an error-message leak can help an adversary map the application’s behaviour and choose the next abuse path more precisely.
Failure mechanism: A long UID cookie value drives the server into an error path that returns sensitive implementation detail instead of handling the condition safely, creating a disclosure channel that can support follow-on exploitation.
Impact: Attackers may gain enough contextual information to improve targeting, evade uncertainty, or combine the leak with other weaknesses, increasing the chance of compromise or data exposure.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
NIST CSF 2.0, NIST SP 800-53 Rev 5 and CIS Controls v8 set the technical controls, while ISO/IEC 27001:2022 defines the regulatory obligations.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST CSF 2.0 | DE.CM-01 — Networks and network services are monitored to detect potential cybersecurity events | Wing FTP exposure needs monitoring for exploitation signs |
| Recommendation — Monitor exposed FTP services for abnormal requests and error spikes. | ||
| NIST SP 800-53 Rev 5 | SI-10 — Information Input Validation | The flaw is triggered by abnormal input that reaches an unsafe error path |
| AU-6 — Audit Record Review, Analysis, and Reporting | Post-exploitation review depends on log analysis of suspicious requests | |
| Recommendation — Validate cookie input and reject oversized values before processing. Review server and access logs for malformed-cookie attempts and follow-on activity. | ||
| ISO/IEC 27001:2022 | A.8.8 — Management of technical vulnerabilities | The term is a KEV-listed vulnerability requiring prioritised remediation |
| Recommendation — Prioritise remediation of the vulnerable Wing FTP Server instance and verify closure. | ||
| CIS Controls v8 | CIS-7 — Continuous Vulnerability Management | Active exploitation makes prioritised vulnerability handling central |
| Recommendation — Track the vulnerable asset, confirm exposure, and accelerate remediation. | ||
Practitioner Guidance
What to watch for: Treat unusual error spikes, malformed cookie values, and repeated requests against login-adjacent endpoints as investigation signals, especially on externally reachable FTP services. Correlate those events with administrative access patterns and any signs of abnormal server-side behaviour.
Governance implication: Keep internet-exposed file transfer systems inside a fast vulnerability triage path, with clear ownership for patch verification and log review. For this kind of KEV-listed issue, exposure confirmation should be treated as a time-sensitive security task, not a routine hygiene item.
Related resources from NHI Mgmt Group
- What breaks when React and Next.js applications expose the server-side deserialization path used in CVE-2025-55182?
- What are the signs that a SharePoint server may have been exploited through CVE-2025-53770?
- Why does an exposed Fluent Bit HTTP server increase the risk of denial of service, information disclosure, or remote code execution?
- CVE-2025-32433 (Erlang Erlang/OTP SSH Server Missing Authentication for Critical Function)