CVE-2025-4538
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 was found in kkFileView 4.4.0. It has been classified as critical. This affects an unknown part of the file /fileUpload. The manipulation of the argument File leads to unrestricted upload. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
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 · high confidencekkFileView 4.4.0 contains an unrestricted file upload vulnerability in the /fileUpload endpoint. Attackers can manipulate the File argument to upload arbitrary file types without proper validation, potentially leading to remote code execution if executable files are uploaded and accessed.
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= 4.4.0CVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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 if Kkfileview is deployedLocate the kkFileView application in your environment - check running Java processes, web application servers, or installed packages. Look for the application directory containing kkfileview.jar or the kkFileView webapp.Affected if kkFileView is installed and running in your environment
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Verify the installed versionCheck the version of your kkFileView installation. This is typically visible in the application startup logs, the filename (kkFileView-4.4.0.jar), or the application's /health or /info endpoint if available.Affected if The version is exactly 4.4.0
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Confirm /fileUpload endpoint existsCheck if the /fileUpload endpoint is accessible in your deployment. This is a REST endpoint that accepts file uploads. Verify its presence by reviewing your application's routing configuration or attempting a request to the endpoint.Affected if The /fileUpload endpoint exists and accepts requests in your environment
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Inspect file upload validationReview the file upload configuration or code for the /fileUpload endpoint. Check if there is server-side validation for file types, content-type checking, or magic byte verification. Look for any whitelist or blacklist of allowed file extensions.Affected if No server-side file type validation is implemented or validation can be bypassed for the /fileUpload endpoint
You are affected if kkFileView version 4.4.0 is running and the /fileUpload endpoint accepts uploads without proper server-side file type validation.
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 dataImplement strict server-side validation for uploaded files including magic byte verification, whitelist allowed file types, store uploads outside webroot, and disable script execution in upload directories.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-4538 — 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-2025-4538 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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