DrupalCMS
CVE-2020-13671
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 · uneditedDrupal core does not properly sanitize certain filenames on uploaded files, which can lead to files being interpreted as the incorrect extension and served as the wrong MIME type or executed as PHP for certain hosting configurations. This issue affects: Drupal Drupal Core 9.0 versions prior to 9.0.8, 8.9 versions prior to 8.9.9, 8.8 versions prior to 8.8.11, and 7 versions prior to 7.74.
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 confidenceDrupal core fails to properly sanitize certain filenames on uploaded files, allowing malicious filenames to bypass extension validation. This can result in files being served with incorrect MIME types or, critically, being executed as PHP scripts on hosting configurations where this is possible (e.g., Apache with mod_php). The vulnerability stems from insufficient input validation on the filename itself during the upload process.
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
DrupalCMS
>= 7.0, < 7.74>= 8.8.0, < 8.8.11>= 8.9.0, < 8.9.9>= 9.0.0, < 9.0.8
FedoraOperating system
= 32= 33CVSS 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
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/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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Determine installed Drupal core versionAccess the Drupal administration dashboard and navigate to Reports > Status report, or check the CHANGELOG.txt file in the Drupal root directory for the version numberAffected if The installed version falls within 7.0 to 7.73, 8.8.0 to 8.8.10, 8.8.x to 8.9.8, or 9.0.0 to 9.0.7 (compare against the affected ranges provided)
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Verify PHP execution is enabled in file upload directoriesCheck the web server configuration (Apache nginx, or IIS) for any directory blocks that allow PHP execution (for example, 'SetHandler application/x-httpd-php' or 'php_flag engine on') within the sites/default/files or similar upload directoriesAffected if PHP execution is permitted in directories where Drupal stores uploaded files, which enables the file to be executed as PHP code
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Confirm file upload functionality is in useInspect the Drupal configuration at Administration > Configuration > Media > File system, or review the sites/default/settings.php file for the 'file_public_path' and 'file_private_path' settings to confirm upload directories are configured and accessibleAffected if File uploads are enabled and the upload directory path is accessible via the web server
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Check for presence of double extensions in uploaded filesReview the Drupal file upload handling code in includes/file.inc or modules/system/src/Form/FileSystemForm.php to see if the file_munge_filename function properly sanitizes double extensions (such as file.php.txt)Affected if The file handling code does not properly sanitize filenames with multiple extensions, allowing files like malicious.php.jpg to bypass extension checks
You are affected if your Drupal core version is below 7.74, 8.8.11, 8.9.9, or 9.0.8 AND PHP execution is enabled in your upload directories, allowing malicious files with double extensions to be executed as PHP code.
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.
dbcve · scoped7.748.8.118.9.9
Upgrade Drupal core to version 9.0.8, 8.9.9, 8.8.11, or 7.74 or later. Until patched, disable file upload functionality or implement additional server-level controls to prevent execution of uploaded files.
Drupal 7.74, 8.8.11, 8.9.9, or 9.0.8 (or later stable releases within each branch)
- 1. Back up your Drupal database and files directory before proceeding.
- 2. Review the Drupal upgrade instructions at https://www.drupal.org/docs/upgrading-drupal
- 3. For Drupal 7: Upgrade to version 7.74 or later.
- 4. For Drupal 8.8.x: Upgrade to version 8.8.11 or later.
- 5. For Drupal 8.9.x: Upgrade to version 8.9.9 or later.
- 6. For Drupal 9.0.x: Upgrade to version 9.0.8 or later.
- 7. Clear Drupal caches after upgrading using 'drush cr' or through the admin UI.
- 8. Verify the fix by testing file uploads with various filename extensions.
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Drupal
Exploited in the wild — priority engagement
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-13671 — 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-2020-13671 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