CVE-2026-6619

A DOM-based Cross-Site Scripting (XSS) vulnerability in Dify's ImagePreview component (file web/app/components/base/image-uploader/image-preview.tsx) is triggered when a user opens a Base64 image in a new tab. The openInNewTab function constructs an ` element using document.write()` with the title parameter directly interpolated into the HTML without sanitization. The title is derived from the filename, which an attacker can control by uploading a file with a malicious name [1].

An attacker can exploit this by crafting a filename containing a quote and script payload, such as ">. When the victim clicks "Open in New Tab" on that uploaded image, the injected script executes in the context of the new window. No authentication is required to upload a file in typical workflows, making this remotely exploitable by any user who can upload content [1].

The impact is execution of arbitrary JavaScript within the victim's browser under the Dify origin, potentially allowing data theft, session hijacking, or further actions within the logged-in session. While the CVSS score is low (3.5) due to conditions like user interaction (clicking a button), the public disclosure of a working proof of concept increases risk [1].

The vendor was notified early but did not respond. As of version 1.13.3, no patch has been released. Users should manually sanitize the filename input or avoid using the "Open in New Tab" feature for Base64 images until a fix is available [1]. Dify has not issued any advisory or update.