GHSA-v3p8-whq6-r5jg: Angular: SSR XSS via Unescaped Content Across DocumentFragment Boundaries in Fallback Raw-Content Elements

### Summary An XSS vulnerability exists in `@angular/platform-server` during server-side rendering (SSR) HTML serialization when traversing ancestor tags across ` ` element boundaries. When an application renders untrusted user input within raw-text tags (` `, ` `, ` `), comments, or text nodes inside a ` ` that is nested within a fallback raw-content element (` `, ` `, ` `, ` `), matching closing tags (e.g., ` `) are not escaped during HTML serialization. …