CVE-2026-5743 Cross-site scripting in SimpLy Gallery
Authenticated attackers with Author access can inject arbitrary scripts via block attributes, leading to stored XSS execution on victim pages.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-5743?
CVE-2026-5743 is a medium-severity cross-site scripting vulnerability in gallerycreator SimpLy Gallery, published on 11 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-79
Which versions are affected by CVE-2026-5743?
How do I fix CVE-2026-5743?
No fix has been published for CVE-2026-5743 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-5743 being exploited?
There is no known exploitation of CVE-2026-5743 in the wild and no public exploit code.
Sources
Also known as GHSA-7jhf-qg59-fxm2.