CVE-2026-3347: The Multi Functional Flexi Lightbox plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the `arv_lb[message]` parameter in all versi...

Description

The Multi Functional Flexi Lightbox plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the `arv_lb[message]` parameter in all versions up to, and including, 1.2 due to insufficient input sanitization and output escaping. This is due to the `arv_lb_options_val()` sanitize callback returning user input without any sanitization, and the stored `message` value being output in the `genLB()` function without escaping. This makes it possible for authenticated attackers, with Administrator-level access, to inject arbitrary web scripts in pages that will execute whenever a user accesses a page or post with the lightbox enabled.

Metrics

CVSS 3.1

5.5/10

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

EPSS Probability

0.26%

17.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

References

Timeline

Published: Mar 21, 2026
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-3347?

The Multi Functional Flexi Lightbox plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the `arv_lb[message]` parameter in all versions up to, and including, 1.2 due to insufficient input sanitization and output escaping. This is due to the `arv_lb_options_val()` sanitize callback returning user input without any sanitization, and the stored `message` value being output in the `genLB()` function without escaping. This makes it possible for authenticated attackers, with Administrator-level access, to inject arbitrary web scripts in pages that will execute whenever a user accesses a page or post with the lightbox enabled.

How severe is CVE-2026-3347?

CVE-2026-3347 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.26% probability of exploitation in the next 30 days.

How do I fix CVE-2026-3347?

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.