CVE-2026-59711 — showdown - Cross-Site Scripting via Unescaped Metadata Title in completeHTMLDocument
showdown contains a cross-site scripting vulnerability in metadata title handling that allows attackers to inject arbitrary HTML and JavaScript. When completeHTMLDocument option…
Published: 2026-07-06 · CVSS: 5.3 · CVSS 4.0
showdown contains a cross-site scripting vulnerability in metadata title handling that allows attackers to inject arbitrary HTML and JavaScript. When completeHTMLDocument option is enabled, unescaped less-than and greater-than characters in markdown frontmatter metadata are inserted directly into HTML title tags, enabling attackers to break out of the title context and execute malicious scripts in the rendered page.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7