CVE-2026-5743: gallerycreator simply gallery Cross-site Scripting

Vulnerability summary

CVE-2026-5743 is a medium (CVSS 6.4) Cross-site Scripting vulnerability in gallerycreator simply gallery. EPSS estimates a 0.45% chance of exploitation in the next 30 days, higher than 37.7% of scored vulnerabilities. Fixed in 3.3.3.2.

Timeline

1. 11-07-2026
   PublishedVulnerability first disclosed.
2. 13-07-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.