Security readout for executives and security teams
Plain-English summary
Drupal had a file-upload handling flaw where certain filenames were not cleaned safely. On some hosting setups, an uploaded file could be treated as the wrong type, including being executed as PHP. CISA lists this CVE as known exploited, so exposed Drupal sites should be treated as urgent.
Executive priority
Prioritize remediation for any internet-facing Drupal instance. Known exploitation and potential full confidentiality, integrity, and availability impact make this more urgent than routine patching, particularly where users can upload files.
Technical view
CVE-2020-13671 is a CWE-434 issue in Drupal Core filename sanitization. The flaw can cause uploaded files to be served with an incorrect MIME type or executed as PHP on certain hosting configurations. It affects Drupal 9.0 before 9.0.8, 8.9 before 8.9.9, 8.8 before 8.8.11, and 7 before 7.74.
Likely exposure
Exposure is most likely on internet-facing Drupal sites running affected core versions, especially sites that allow authenticated users to upload files. Risk depends partly on hosting behavior for uploaded files and PHP execution.
Exploitation context
CISA KEV status supports known exploitation. The supplied sources do not describe exploit volume, targets, or public exploit details. CVSS indicates network access, low attack complexity, and low privileges are sufficient.
Researcher notes
The key exposure question is whether affected Drupal versions combine with upload-capable accounts and hosting behavior that can misinterpret uploaded filenames. Evidence in the bundle supports affected versions, CWE-434 classification, fixed releases, CVSS 8.8, and KEV status, but not detailed exploit telemetry.
Mitigation direction
- Upgrade Drupal Core to 7.74, 8.8.11, 8.9.9, 9.0.8, or later.
- Apply relevant Fedora package updates if Drupal was installed from Fedora packages.
- Review Drupal vendor advisory SA-CORE-2020-012 for deployment-specific guidance.
- Limit file upload permissions to trusted roles until remediation is confirmed.
- Review hosting configuration for uploaded-file execution and MIME handling.
Validation and detection
- Inventory all Drupal Core versions across production, staging, and legacy sites.
- Confirm affected branches are upgraded to the fixed versions or later.
- Identify public routes and roles that can upload files.
- Review uploaded-file directories for suspicious filenames or unexpected executable handling.
- Check CISA KEV tracking for operational prioritization and due-date policy alignment.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-434: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-13671 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.drupal.org/sa-core-2020-012CVE reference · x_refsource_CONFIRM
- FEDORA-2020-6f1079934cCVE reference · vendor-advisory, x_refsource_FEDORA
- FEDORA-2020-d50d74d6f2CVE reference · vendor-advisory, x_refsource_FEDORA
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-13671CVE reference · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.