Mixed Media Gallery Blocks <= 3.3.3.1 — Authenticated (Author+) Stored Cross-Site Scripting via sliderMaxHeight Block Attribute

Am I affected?

• Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under SimpLy Gallery.
• No admin access? Run a passive check of your site. It reads public files only.

What to do

1. Update to version 3.3.3.2, or a newer patched version
2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
3. Watch SimpLy Gallery to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to Muhammad Yudha - DJ.

The SimpLy Gallery Block & Lightbox plugin for WordPress is vulnerable to Stored Cross-Site Scripting via block attributes in all versions up to, and including, 3.3.3.2. This is due to insufficient input sanitization and output escaping on the sliderMaxHeight block attribute in the pgc_sgb_render_callback() function. The vulnerability exists because the pgc_sgb_sanitize_custom_css() function uses a flawed regex pattern that only removes event handlers with quoted values (e.g., onfocus="alert()") but fails to catch unquoted event handlers (e.g., onfocus=alert(document.cookie)), allowing the malicious code to bypass sanitization. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts in pages via block attributes that will execute whenever a user accesses an injected page.

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

• Advisorywordfence.com

Related CVEs

Timeline

1. Jul 10, 2026

   CVE published

   Severity medium, CVSS 6.4

2. Nov 13, 2026

   Record last updated