# FancyBox for WordPress <= 3.4.2 - Unauthenticated Stored Cross-Site Scripting via Comment Link URLs

- **ID:** WPSEC-2026-2802
- **Plugin:** FancyBox for WordPress (`fancybox-for-wordpress`), https://wordpress.org/plugins/fancybox-for-wordpress/
- **Affected versions:** from 3.1.0 before 3.4.3
- **Fixed in:** 3.4.3 (Update to 3.4.3 or later.)
- **Severity:** High 7.2 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N)
- **Weakness:** CWE-79
- **Usage among sites WPSec scans:** plugin Medium, affected versions Medium (as of 2026-11-10)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/fancybox-for-wordpress
- **Fix released:** 2026-11-09
- **Published:** 2026-11-10
- **URL:** https://wpsec.com/vuln/WPSEC-2026-2802/

## Description

The FancyBox for WordPress plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the URL of links opened in the lightbox in all versions up to, and including, 3.4.2. This is due to the lightbox placing the entity-decoded link URL into the video template without escaping. Any link wrapping an image, including a smiley in a comment, is turned into a lightbox link. This makes it possible for unauthenticated attackers to inject arbitrary web scripts through a crafted link in a comment. The scripts run when a user opens the link in the lightbox.

## References

- https://wpsec.com/vuln/WPSEC-2026-2802/
- https://plugins.svn.wordpress.org/fancybox-for-wordpress/tags/3.4.3/
- https://wordpress.org/plugins/fancybox-for-wordpress/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-2802/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.