Project: 
Date: 
2026-June-17
Vulnerability: 
Improper validation
Affected versions: 
<10.5.12 || >=10.6.0 <10.6.11 || >=11.2.0 <11.2.14 || >=11.3.0 <11.3.12 || 11.0.* || 11.1.*
CVE IDs: 
CVE-2026-55808
Description: 

The JSON:API and REST modules allow you to upload image files to image fields.

The validation rules check the file extension of the uploaded file but not the file MIME type. This may allow a malicious user to upload a file that is not an image.

Certain web-server configurations may serve the uploaded file with its actual MIME type rather than an image type. This may lead to cross-site scripting (XSS) or other unexpected behavior.

Solution: 

Install the latest version:

Drupal 11

Drupal 10

Drupal 11.1.x, Drupal 11.0.x, Drupal 10.4.x, and below are end-of-life and do not receive security coverage. (Drupal 8 and Drupal 9 have both reached end-of-life.)

Reported By: 
Coordinated By: