CVE-2023-40053
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA vulnerability has been identified within Serv-U 15.4 that allows an authenticated actor to insert content on the file share function feature of Serv-U, which could be used maliciously.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA vulnerability in Serv-U 15.4 file share feature allows authenticated users to inject malicious content, likely representing a client-side injection (XSS) vulnerability where user-supplied input in the file share function is not properly sanitized before rendering.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 15.4.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Changed
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Serv-U installation versionCheck the installed Serv-U version through the application interface, command line, or installed packages. Common methods include: reviewing the software inventory, checking the application about/version info, or running 'serv-u -v' if available.Affected if The installed version is exactly 15.4.0
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Confirm file share feature is enabledLocate the Serv-U configuration settings for the file share functionality. This is typically found in the Serv-U administrative console under file sharing or sharing settings.Affected if The file share feature is currently enabled in the Serv-U configuration
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Verify user authentication is activeConfirm that user authentication is enabled and users can log in to Serv-U. Check authentication settings in the admin console or configuration files.Affected if User authentication is enabled and users can access the file share interface with their credentials
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Check file share permissions configurationReview the file share permission settings to determine which authenticated users have access to create or modify shared content.Affected if Any authenticated users (including untrusted or low-privilege users) have permissions to use the file share feature
The environment is affected if running Serv-U version 15.4.0 with the file share feature enabled and accessible to authenticated users, as the XSS vulnerability exists in the file share input handling.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply available vendor patches for Serv-U 15.4; until patched, limit file share permissions to trusted users only and implement output encoding for content displayed in the file share interface.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-40053 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-40053 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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