CVE-2020-13671 — core
HIGHCVE-2020-13671 is a high-severity (CVSS 8.8) Unrestricted File Upload vulnerability in drupal/core. It is in CISA's Known Exploited Vulnerabilities catalog (added 2022-01-18) — treat it as actively exploited and patch now. A fix is available for drupal/core — see the affected versions and patch details below.
Drupal core Unrestricted Upload of File with Dangerous Type
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2022-01-18. Federal agencies were required to remediate by 2022-07-18.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2020-13671.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2020-13671 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
drupal/core🐘drupal/core🐘drupal/core🐘drupal/core🐘drupal/drupal🐘drupal/drupal🐘drupal/drupal🐘drupal/drupalReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Drupal 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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | drupal/core | ≥ 9.0.0&&< 9.0.8 | 9.0.8composer require drupal/core:^9.0.8 |
| 🐘Packagist | drupal/core | ≥ 8.9.0&&< 8.9.9 | 8.9.9composer require drupal/core:^8.9.9 |
| 🐘Packagist | drupal/core | ≥ 8.0.0&&< 8.8.11 | 8.8.11composer require drupal/core:^8.8.11 |
| 🐘Packagist | drupal/core | ≥ 7.0.0&&< 7.74 | 7.74composer require drupal/core:^7.74 |
| 🐘Packagist | drupal/drupal | ≥ 7.0.0&&< 7.74 | 7.74composer require drupal/drupal:^7.74 |
| 🐘Packagist | drupal/drupal | ≥ 8.0.0&&< 8.8.11 | 8.8.11composer require drupal/drupal:^8.8.11 |
Affected Products
drupaldrupalfedorafedoraprojectResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for drupal/core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update drupal/core to 9.0.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-13671 is resolved across your whole dependency graph.
Workarounds
Treat uploaded files as untrusted until proven otherwise: validate the actual content type rather than the supplied extension, store uploads outside the web root on a volume mounted without execute permission, and rename them to server-generated identifiers so an attacker cannot choose the path a request will later resolve.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Frequently Asked Questions
Is CVE-2020-13671 in your dependencies?
Find it across Packagist, including transitive dependencies.