What the vulnerability does
01Description
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.
Explanation of Vulnerability in Simple Terms
02Summary
SimpLy Gallery versions 3.3.3.1 and earlier contain a cross-site scripting vulnerability that allows authenticated users to inject malicious scripts. The vulnerability affects the scope beyond the vulnerable component, potentially impacting other users and site functionality. Administrators should update to a version newer than 3.3.3.1 to remediate this issue.
What an attacker can do
03Attacker Capabilities
Inject malicious scripts that execute in other users' browsers and affect site functionality.
Potential impact on your site
04Site Impact
Authenticated users can inject scripts affecting other visitors and site operations; data exposure or modification possible.
Conditions required to exploit
05Prerequisites
Attacker must have a low-privilege user account on the site; no user interaction required.
Key dates
06Disclosure timeline
July 11, 2026
CVE published
July 13, 2026
Record updated
