CVE-2021-31707
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 · uneditedPermissions vulnerability found in KiteCMS allows a remote attacker to execute arbitrary code via the upload file type.
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 confidenceKiteCMS contains a file upload vulnerability where insufficient permission validation allows a remote attacker to upload malicious files (such as PHP scripts) and execute arbitrary code on the server through the web application.
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 dataall versionsCVSS 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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Confirm KiteCMS installationCheck for KiteCMS files by looking for common paths such as /admin/, /kitecms/, or checking page source for 'KiteCMS' or 'kitecms' strings. Check HTTP response headers or footer of web pages for KiteCMS branding.Affected if KiteCMS is found to be installed on the server.
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Identify file upload functionalityNavigate to the admin panel or user upload pages. Look for features labeled as file upload, media upload, attachment, or image upload. Check for forms accepting file input with enctype='multipart/form-data'.Affected if File upload functionality is accessible (no authentication required or weak permission checks).
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Check user permission enforcementInspect the upload handling code or test with a low-privileged or anonymous user account. Attempt to access upload endpoints without proper authentication to see if permission validation is enforced.Affected if Upload endpoints are accessible without proper authentication or permission validation is missing.
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Review upload directory configurationCheck server configuration files or KiteCMS settings to determine where uploaded files are stored. Verify if uploads are stored within the webroot or outside it.Affected if Uploaded files are stored inside the webroot directory accessible via HTTP.
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Check script execution settingsInspect web server configuration (Apache .htaccess, Nginx config) and upload directory for restrictions on executing script files (PHP, JSP, ASP, etc.). Look for handlers or directives that allow script execution in upload paths.Affected if Script execution is allowed in the upload directory or no execution restrictions are in place.
If KiteCMS is installed, has an accessible file upload feature, lacks proper permission checks, stores files within the webroot, and allows script execution in upload directories, the environment is affected by CVE-2021-31707.
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 allowlist-based file type validation, verify user permissions before upload, store uploads outside the webroot, and disable script execution in upload directories.
- Consultation3.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,568.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-31707 — 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-2021-31707 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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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.
- 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
- No spam, self-promotion, credentials, or personal data