CVE-2026-6454: XSS (CVSS 6.4)

Description

The Firelight Lightbox plugin for WordPress is vulnerable to Stored DOM Cross-Site Scripting in versions up to and including 2.3.20. This is due to insufficient sanitization of the href attribute value within the FancyBox V2 PDF beforeLoad JavaScript callback generated in inc/fancybox-2.php, where this.href is string-concatenated directly into an HTML string without escaping, allowing a stored href containing entity-encoded double-quotes to break out of the data attribute and inject arbitrary event handlers into the DOM. This makes it possible for authenticated attackers with contributor-level access and above to inject arbitrary web scripts into pages that execute whenever a user clicks the malicious PDF link.

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CVSS v3.1 Score

6.4

MEDIUM

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

EPSS — Exploit Prediction

0.0021

Probability of exploitation

0.11%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

https://plugins.trac.wordpress.org/browser/easy-fancybox/tags/2.3.18/fancybox/2.2.0/jquery.fancybox.js#L1235 https://plugins.trac.wordpress.org/browser/easy-fancybox/tags/2.3.18/fancybox/2.2.0/jquery.fancybox.js#L280 https://plugins.trac.wordpress.org/browser/easy-fancybox/tags/2.3.18/inc/fancybox-2.php#L322 https://plugins.trac.wordpress.org/browser/easy-fancybox/trunk/fancybox/2.2.0/jquery.fancybox.js#L1235 https://plugins.trac.wordpress.org/browser/easy-fancybox/trunk/fancybox/2.2.0/jquery.fancybox.js#L280 https://plugins.trac.wordpress.org/browser/easy-fancybox/trunk/inc/fancybox-2.php#L322 https://plugins.trac.wordpress.org/changeset?reponame=&old=3610643%40easy-fancybox&new=3610643%40easy-fancybox https://www.wordfence.com/threat-intel/vulnerabilities/id/8396c124-9c72-4801-8964-1cd5fbd52d20?source=cve

Frequently Asked Questions

What is CVE-2026-6454? +

The Firelight Lightbox plugin for WordPress is vulnerable to Stored DOM Cross-Site Scripting in versions up to and including 2.3.20. This is due to insufficient sanitization of the href attribute value within the FancyBox V2 PDF beforeLoad JavaScript callback generated in inc/fancybox-2.php, where this.href is string-concatenated directly into an HTML string without escaping, allowing a stored href containing entity-encoded double-quotes to break out of the data attribute and inject arbitrary event handlers into the DOM. This makes it possible for authenticated attackers with contributor-level access and above to inject arbitrary web scripts into pages that execute whenever a user clicks the malicious PDF link. It has a CVSS v3.1 base score of 6.4 (MEDIUM).

How severe is CVE-2026-6454? +

CVE-2026-6454 has a CVSS v3.1 score of 6.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0021, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-6454? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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