symfony/ux-icons: XSS via unsanitized SVG content in local files and Iconify on-demand responses

Description The uxicon Twig function is marked issafe='html', so Twig never escapes its output. Icon::toHtml inlines the SVG source verbatim into the page. Browsers execute elements and on event-handler attributes found inside inline SVG, making any unsanitized icon a vector for cross-site...