CVE-2026-5361: Envira Gallery <= 1.12.4 - Authenticated (Author+) Stored Cross-Site Scripting via 'arrows' Parameter

The Envira Gallery Lite plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the REST API in versions up to and including 1.12.4. This is due to insufficient input sanitization in the updategallerydata() function and improper output escaping in the galleryinit() function. The sanitizeconfigvalues() function only sanitizes the justifiedgallerytheme and justifiedrowheight parameters, but does not sanitize the arrows parameter. When the arrows value is output in the inline JavaScript configuration, it uses escattr() which is designed for HTML attribute contexts, not JavaScript contexts, allowing JavaScript expression injection. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.