CVE-2026-49210 Symfony UX: XSS in symfony/ux-live-component via attacker-controlled child component tag

Symfony UX is a JavaScript ecosystem for Symfony. From 2.8.0 until 2.36.0 and 3.1.0, Symfony\UX\LiveComponent\Util\ChildComponentPartialRenderer::createHtml interpolates the client-controlled childrenid.tag value from LiveComponentSubscriber and InterceptChildComponentRenderSubscriber directly in...

CVE-2026-49210 Symfony UX: XSS in symfony/ux-live-component via attacker-controlled child component tag

Symfony UX is a JavaScript ecosystem for Symfony. From 2.8.0 until 2.36.0 and 3.1.0, Symfony\UX\LiveComponent\Util\ChildComponentPartialRenderer::createHtml interpolates the client-controlled childrenid.tag value from LiveComponentSubscriber and InterceptChildComponentRenderSubscriber directly in...

symfony/ux-live-component XSS via attacker-controlled child component tag

Description Symfony\UX\LiveComponent\Util\ChildComponentPartialRenderer::createHtml interpolates the $childTag argument directly into the HTML output as a tag name, without escaping or validation. The value originates from client-controlled JSON childrenid.tag parsed by LiveComponentSubscriber an...