CVE-2025-40540
CRITICALDescription
A type confusion vulnerability exists in Serv-U which when exploited, gives a malicious actor the ability to execute arbitrary native code as privileged account. This issue requires administrative privileges to abuse. On Windows deployments, the risk is scored as a medium because services frequently run under less-privileged service accounts by default.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 37% of all known CVEs.
References
Related Vulnerabilities
Other CWE-704 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2025-41646 | Critical | 9.8 | 47% | - | Fix |
| CVE-2017-5115 | High | 8.8 | 26% | - | Fix |
| CVE-2018-3843 | High | 8.8 | 24% | - | - |
| CVE-2018-12453 | High | 7.5 | 24% | - | Fix |
| CVE-2017-3106 | High | 8.8 | 22% | - | - |
| CVE-2018-5007 | High | 8.8 | 18% | - | - |
Common questions
How do I fix CVE-2025-40540?
Upgrade serv-u to 15.5.4 or later.
Is CVE-2025-40540 being actively exploited?
Not that we know of. CVE-2025-40540 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.45% is the estimated probability that it will be exploited in the next 30 days. That is higher than 37% of all scored CVEs.
How severe is CVE-2025-40540?
CVE-2025-40540 has a CVSS v3 base score of 9.1, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2025-40540 affect?
Published advisories record a fix for serv-u (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2025-40540
Markdown
[](https://tridentstack.com/cve/CVE-2025-40540)HTML
<a href="https://tridentstack.com/cve/CVE-2025-40540"><img src="https://tridentstack.com/cve/badge/CVE-2025-40540.svg" alt="CVE-2025-40540"></a>Find and fix vulnerabilities across your fleet
TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-02-24.