CVE-2026-8625: Dear Flipbook <= 2.4.30 - Authenticated (Contributor+) Stored Cross-Site Scripting via '.df-element' Element Inner HTML
The Dear Flipbook – PDF Flipbook, 3D Flipbook, PDF embed, PDF viewer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'postcontent (Custom HTML block inner HTML)' parameter in all versions up to, and including, 2.4.30 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. A Contributor-level attacker can insert a crafted .df-element div with data-df-lightbox='thumb' via a Custom HTML block, whose inner HTML is passed as the title argument to parseThumbs() at render time, enabling both innerHTML injection into a span element and attribute breakout via an onerror handler on a constructed img element.
Affected Software
Event History
Frequently Asked Questions
Which users can exploit this issue?
An attacker must be authenticated with at least Contributor-level access. This includes any higher-privileged WordPress role that can create or edit content using the affected functionality.
What content must an attacker be able to create to trigger the vulnerability?
The attacker needs to place a crafted .df-element div with data-df-lightbox='thumb' in a Custom HTML block. Its inner HTML is used during rendering in a way that permits script injection, including an attribute breakout using an onerror handler.
When does the injected script execute?
The payload is stored in page content and executes when a user accesses the injected page. No additional user interaction is required beyond visiting that page.
Which plugin versions are affected?
All Dear Flipbook versions up to and including 2.4.30 are affected.