CVE-2026-109392

Description

Pimcore through 2026.3.1 contains a stored cross-site scripting vulnerability that allows authenticated backend users to inject scripts by storing unescaped URLs in ExternalImage fields. Attackers with data object edit permission can store attribute-breaking payloads that execute JavaScript in the admin origin when other users open version preview or diff views.

References

• https://github.com/pimcore/admin-ui-classic-bundle/blob/2.3/templates/admin/data_object/data_object/preview_version.html.twig#L198
• https://github.com/pimcore/pimcore
• https://github.com/pimcore/pimcore/blob/v2026.3.1/models/DataObject/ClassDefinition/Data/ExternalImage.php#L169-L203
• https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/rJCbgCKjMe
• https://www.vulncheck.com/advisories/pimcore-through-2026.3.1-stored-xss-via-externalimage-field-version-preview