LowDRUPAL-CORE-2026-009BIT-drupal-2026-55808CVE-2026-55808

DRUPAL-CORE-2026-009 in drupal/core

Published 17 Jun 2026 · Updated 10 Sept 2026

Affected package

drupal/coreComposer
Affected
<10.5.12 · >=10.6.0 <10.6.11 · >=11.2.0 <11.2.14 · >=11.3.0 <11.3.12 · >=11.0.0 <11.1.0 · >=11.1.0 <11.2.0
Fixed in
10.5.12, 10.6.11, 11.1.0, 11.2.0, 11.2.14, 11.3.12
Update to the fixed version for your release line, for example:composer require drupal/core:^11.3.12

Details

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.

Is DRUPAL-CORE-2026-009 in any of your client repos?

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References

Advisory data from OSV.dev (opens OSV.dev in a new tab), refreshed daily.