CVE-2026-59711
MEDIUM
NVD
CVSS Score
6.1
Severity
MEDIUM
Published
Jul 06, 2026
Vendor
unknown
Description
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.