Defuddle cleans up HTML pages. Prior to 0.19.1, site extractors interpolate page-derived image alt and src values, og:image values, and video descriptions into HTML strings without context-appropriate escaping, and buildExtractorResponse() returns this contentHtml without the main pipeline's DOM-based sanitization. The affected paths include src/extractors/x-article.ts, src/extractors/substack.ts, and src/extractors/youtube.ts. A malicious page or attacker-controlled content on a matching domain can inject event-handler attributes or javascript URLs that execute when a victim or downstream application renders the extracted HTML. This issue is fixed in version 0.19.1.

CVE-2026-61824 affects Defuddle, an HTML page cleanup library, in versions prior to 0.19.1. Site extractors for X (Twitter), Substack, and YouTube interpolate page-derived values such as image alt/src attributes, og:image metadata, and video descriptions directly into HTML strings without proper escaping. The buildExtractorResponse() function returns this unsanitized contentHtml, bypassing the main pipeline's DOM-based sanitization. This allows a malicious page or attacker-controlled content to inject event-handler attributes or javascript: URLs into the extracted HTML. When a victim or downstream application renders this HTML, arbitrary JavaScript can execute, constituting a stored/reflected XSS attack vector. The affected source files are src/extractors/x-article.ts, src/extractors/substack.ts, and src/extractors/youtube.ts. The vulnerability has been patched in Defuddle version 0.19.1.