Unrestricted File UploadWeakness · CWE-434

CVE-2021-47819

CRITICAL · 9.8 CVSS v3.1 Published 2026-01-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click

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
ProjeQtOr Project Management 9.1.4 contains a file upload vulnerability that allows guest users to upload malicious PHP files with arbitrary code execution capabilities. Attackers can upload a PHP script through the profile attachment section and execute system commands by accessing the uploaded file with a specially crafted request parameter.

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 confidence

ProjeQtOr Project Management version 9.1.4 has a critical file upload vulnerability in the profile attachment feature that permits unauthenticated guest users to upload PHP files containing malicious code. The uploaded files can then be accessed and executed via a specially crafted request parameter, allowing complete remote code execution on the affected server.

MitigationRestrict or disable guest user file upload capabilities immediately. Implement strict allowlist-based file type validation, disable PHP execution in upload directories, and validate request parameters used to access uploaded files. Upgrade to the vendor patched version once available.

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
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 checks

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

  1. Identify ProjeQtOr version
    Locate the version file in the ProjeQtOr installation directory, typically in a VERSION file or within the application header files. Access the admin panel and navigate to About or System Information to view the installed version number.
    Affected if The installed version is 9.1.4 or earlier (the summary indicates 9.1.4 is affected)
  2. Verify guest user status
    Check if guest user accounts are enabled in ProjeQtOr by accessing the Administration menu, then User Management. Look for any user account with the 'Guest' profile type or guest access permissions.
    Affected if Guest user accounts are active and allowed to log in to the system
  3. Confirm file upload permission for guests
    Navigate to the profile or user management section and examine the attachment/file upload permissions assigned to the Guest profile. Look for any permission grants related to uploading files or attachments.
    Affected if Guest profile has file upload or attachment permissions enabled
  4. Check upload directory PHP execution
    Locate the upload directory (typically /upload or similar in the web root) and verify the web server configuration. Check if PHP execution is allowed in this directory by examining .htaccess rules (Apache) or nginx configuration for the upload path.
    Affected if PHP files can be executed from the upload directory (no execution restriction in place)
  5. Scan for suspicious uploaded files
    Search the upload directories for .php files. Use command-line tools: find /path/to/upload -name "*.php" (Linux) or directory listing via file manager. Examine file names for patterns like shell.php, cmd.php, or encoded strings.
    Affected if Unexpected or unknown PHP files exist in upload directories

A system is affected if it runs ProjeQtOr version 9.1.4, has guest user access enabled, permits file uploads for guest accounts, and allows PHP execution in upload directories, potentially evidenced by unexpected PHP files in upload paths.

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

Restrict or disable guest user file upload capabilities immediately. Implement strict allowlist-based file type validation, disable PHP execution in upload directories, and validate request parameters used to access uploaded files. Upgrade to the vendor patched version once available.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,600
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-47819 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-47819 in production — separate from our analysis above.

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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
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  • Version or environment caveats, and links to real fixes
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