mediumCVE-2026-6454

Firelight Lightbox <= 2.3.20 - Authenticated (Contributor+) Stored DOM Cross-Site Scripting via PDF beforeLoad 'href' Attribute

Q: What is affected by CVE-2026-6454?

firelightwp Firelight Lightbox versions listed as affected should be reviewed: <= 2.3.20, up to and including 2.3.20.

Q: What should I fix first?

Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.

Q: How do I confirm the fix worked?

Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.

Q: How are Fixnx security risk categories chosen?

Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.

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.

Browse WordPress security risks

ProductFirelight Lightbox

CVSS6.4

EPSSNot scored yet

UpdatedJuly 24, 2026

Quick answer

firelightwp Firelight Lightbox should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.

Who is affected

Affected versions

<= 2.3.20
up to and including 2.3.20

Fixed versions

2.3.21

How to fix it

CVE-2026-6454 affects Firelight Lightbox and involves cross-site scripting. Successful exploitation may run attacker-controlled script in a trusted user's browser and expose session or application data. Prioritize deployments that process untrusted input, expose the affected feature, or hold sensitive data. Upgrade Firelight Lightbox to 2.3.21 or a later vendor-supported fixed release.

Inventory every deployment, device, package, plugin, container, build, and environment that uses Firelight Lightbox.
Compare the installed version with the recorded affected range: <= 2.3.20, *-2.3.20.
Upgrade Firelight Lightbox to 2.3.21 or a later vendor-supported fixed release.
Until patched, disable the affected Firelight Lightbox feature or plugin and restrict its public and administrator endpoints.
Review configuration, roles, tokens, network paths, and exposed endpoints connected to Firelight Lightbox; remove access that is not required.
Review submissions, stored content, administrator activity, CSP reports, and web logs for script payloads or suspicious browser requests.
If exploitation is suspected, isolate affected assets, preserve evidence, rotate exposed credentials or keys, restore trusted data, and rebuild compromised systems before returning them to service.

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Verify the fix

Confirm every affected asset now runs the fixed vendor-supported release or has the documented mitigation for CVE-2026-6454 in place.
Use a safe regression test to confirm the affected cross-site scripting path no longer produces the vulnerable behavior.
Confirm temporary access controls, endpoint restrictions, network blocks, and least-privilege settings remain effective after the update.
Review post-remediation logs and rerun Fixnx plus the relevant package, dependency, firmware, browser, or product-specific security check.
Document affected assets, versions, changes, validation evidence, reviewed logs, and any credential rotation, cleanup, or replacement completed.

Related categories

WordPress PHP Cross-site Scripting

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Trusted references

Source advisoryNVD, Wordfence Source advisoryNVD, Wordfence Source advisoryNVD, Wordfence Source advisoryNVD, Wordfence Source advisoryNVD, Wordfence Source advisoryNVD, Wordfence Source advisoryNVD, Wordfence Source advisoryNVD, Wordfence Wordfence advisoryNVD, Wordfence Wordfence advisoryNVD, Wordfence

FAQ

What is affected by CVE-2026-6454?

firelightwp Firelight Lightbox versions listed as affected should be reviewed: <= 2.3.20, up to and including 2.3.20.

What should I fix first?

Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.

How do I confirm the fix worked?

Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.

How are Fixnx security risk categories chosen?

Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.