ZeroDay Findings
Sign inSign up

Findings

Vulnerability · CVE-2020-13671

Drupal core Un-restricted Upload of File

Published Nov 20, 2020 · corrected/updated Jun 16, 2026 · Drupal Drupal Core · evidence confidence very high

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.

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

CVE-2020-13671 is a high public vulnerability record for Drupal Drupal Core. CISA lists it as known exploited. Published remediation guidance: Apply updates per vendor instructions. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether Drupal Drupal Core is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: drupal/drupal; fedoraproject/fedora (32); fedoraproject/fedora (33); Drupal Drupal Core. Published remediation guidance: Apply updates per vendor instructions. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: CVSS 8.8, EPSS 35.4%. CISA lists it as known exploited. Weakness classes: CWE-434. Sources contributing to this record: cisa_kev, cve_org, epss, nvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Confirmed in CISA KEV since Apr 12, 2021. Listed in CISA KEV and VulnCheck KEV.

  • Patch and remediation

    Apply updates per vendor instructions. CISA due date Jul 18, 2022.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Technology hubs

Drupal

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Nov 20, 2020 · Catalog

    Detected

    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.

  2. Jan 18, 2022 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Jul 18, 2022 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jun 16, 2026 · Catalog

    Updated

    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

  • cpe drupal/drupalversion unspecified
  • cpe fedoraproject/fedora32
  • cpe fedoraproject/fedora33
  • vendor Drupal Drupal Coreversion unspecified
  • vendor Drupal Drupal coreversion unspecified

Sources

  • CISA KEVConfirmed exploitationCVE-2020-13671

    Improper sanitization in the extension file names is present in Drupal core.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2020-13671

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2020-13671

    30-day exploitation probability 35.4%

    first.org
  • NIST NVDVulnerability recordCVE-2020-13671

    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 ver

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2020-13671

    Improper sanitization in the extension file names is present in Drupal core.

    vulncheck.com

References