Unrestricted File UploadWeakness · CWE-434

CVE-2023-27753

HIGH · 8.0 CVSS v3.1 Published 2026-05-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable

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 · unedited
An arbitrary file upload vulnerability in MK-Auth 23.01K4.9 allows attackers to execute arbitrary code via uploading a crafted PHP file.

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 confidence

MK-Auth 23.01K4.9 contains an arbitrary file upload vulnerability that allows attackers to upload malicious PHP files and execute arbitrary code on the server. The application lacks proper file type validation and secure file storage controls for uploaded files.

MitigationImplement strict server-side validation of file types (extension, MIME type, and magic bytes), store uploads outside the web root with randomized filenames, and disable PHP execution in upload directories.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS 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
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify MK-Auth installation and version
    Locate MK-Auth installation directories and check version files (typically in config files, about page, or version metadata files). Compare the installed version to 23.01K4.9.
    Affected if The installed version matches 23.01K4.9 exactly or is lower (earlier releases of the 23.01 branch).
  2. Locate file upload functionality
    Identify which web paths or API endpoints handle file uploads in MK-Auth. Common paths include /upload, /arquivos, /files, or similar endpoints used for user document or image uploads.
    Affected if The application has active file upload endpoints that accept user-submitted files.
  3. Verify upload storage location
    Inspect the web server configuration and application settings to determine where uploaded files are stored. Check if uploads are stored inside the web root (publicly accessible) or outside of it.
    Affected if Uploaded files are stored within the web root directory, making them directly accessible via HTTP requests.
  4. Check PHP execution in upload directories
    Examine web server config (Apache .htaccess, Nginx directives) and the upload folder configuration to verify if PHP execution is allowed or disabled in upload directories.
    Affected if PHP execution is permitted in directories where uploaded files are stored.
  5. Assess file type validation
    Review the application's upload handling code or configuration to determine what validation (if any) is performed on uploaded files. Look for extension checks, MIME type validation, and magic byte verification.
    Affected if The application lacks server-side validation of file extensions, MIME types, and content (magic bytes), or allows PHP file extensions to be uploaded.

A user is affected if MK-Auth version 23.01K4.9 or earlier is installed AND the application accepts file uploads AND uploads are stored in a web-accessible location with PHP execution enabled AND proper file type validation is missing.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement strict server-side validation of file types (extension, MIME type, and magic bytes), store uploads outside the web root with randomized filenames, and disable PHP execution in upload directories.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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Scan for this in your stack

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dbcve dependency scanner

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-27753 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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