Threats / Drupal / CVE-2020-13671
CVE-2020-13671
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Drupal core vulnerability
Improper sanitization of extension file names in Drupal core allows arbitrary file upload, enabling remote code execution and system compromise.
Verdict
Today item — known-exploited.
An unauthenticated or low-privileged attacker can upload malicious files with unsanitized names to execute arbitrary code on the server. This vulnerability has been actively exploited in the wild.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
4 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-01-18).
Probability (EPSS)
EPSS 0.04269 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Drupal, Drupal core. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-434 Unrestricted File Upload — weakness family: Path traversal / file.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a file upload request with a specially crafted extension name that bypasses sanitization filters.
Business
Attackers gain ability to upload executable files to the web server without proper validation.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I place the malicious file in a web-accessible directory where it can be executed by the server.
Business
The uploaded file becomes executable, allowing arbitrary code execution in the application context.
3
Lateral reach — past segmentation narrative 3
Attacker
I trigger execution of the uploaded file through HTTP requests or automatic server processing.
Business
Complete compromise of the Drupal installation and underlying server infrastructure occurs.
4
Data at risk — exfiltration narrative 4
Attacker
I establish persistent access and exfiltrate sensitive data or modify application content.
Business
Data breach, service disruption, and reputational damage to the organization hosting the Drupal site.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05