CVE-2026-4665: The WP Carousel Free plugin for WordPress is vulnerable to Stored Cross-Site Scripting via crafted fancybox `data-caption` attributes in all versions ...

Description

The WP Carousel Free plugin for WordPress is vulnerable to Stored Cross-Site Scripting via crafted fancybox `data-caption` attributes in all versions up to, and including, 2.7.10. This is due to the `fancybox-config.js` script reading the carousel container's `id` attribute directly from the DOM to construct a jQuery selector without sanitization. When a Contributor crafts an HTML block with a malformed carousel container ID (containing characters invalid for jQuery selectors), the custom fancybox configuration throws a JavaScript error and fails to initialize. This causes the bundled fancybox library (v3.5.7) to fall back to its default caption handling, which renders the `data-caption` attribute content as raw HTML. Since WordPress allows `data-*` attributes through `wp_kses_post()`, 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 clicks an image in the crafted carousel lightbox.

Metrics

CVSS 3.1

6.4/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

EPSS Probability

0.28%

19.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

References

Timeline

Published: May 5, 2026
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-4665?

The WP Carousel Free plugin for WordPress is vulnerable to Stored Cross-Site Scripting via crafted fancybox `data-caption` attributes in all versions up to, and including, 2.7.10. This is due to the `fancybox-config.js` script reading the carousel container's `id` attribute directly from the DOM to construct a jQuery selector without sanitization. When a Contributor crafts an HTML block with a malformed carousel container ID (containing characters invalid for jQuery selectors), the custom fancybox configuration throws a JavaScript error and fails to initialize. This causes the bundled fancybox library (v3.5.7) to fall back to its default caption handling, which renders the `data-caption` attribute content as raw HTML. Since WordPress allows `data-*` attributes through `wp_kses_post()`, 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 clicks an image in the crafted carousel lightbox.

How severe is CVE-2026-4665?

CVE-2026-4665 has a CVSS score of 6.4/10 (MEDIUM severity). The EPSS model estimates a 0.28% probability of exploitation in the next 30 days.

How do I fix CVE-2026-4665?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.