CVE-2026-55691 — EmbedVideo Extension : Stored XSS via unsanitized class passed to template
The EmbedVideo Extension is a MediaWiki extension which adds a parser function called #ev and various parser tags for embedding video clips from various video sharing services. …
Published: 2026-09-15 · CVSS: 8.6 · CVSS 3.1
The EmbedVideo Extension is a MediaWiki extension which adds a parser function called #ev and various parser tags for embedding video clips from various video sharing services. Prior to 4.1.0, EmbedHtmlFormatter::toHtml in includes/EmbedService/EmbedHtmlFormatter.php passes the user-supplied class value directly to sprintf while constructing a figure element. A quote in the class value can terminate the class attribute and inject arbitrary HTML attributes or markup into the rendered page. A user able to edit a wiki page can store JavaScript that executes for visitors who render the affected content. This issue is fixed in version 4.1.0.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7