p PatchFirst

CVE-2026-59711

CVE-2026-59711 · showdown - Cross-Site Scripting via Unescaped Metadata Title in completeHTMLDocument

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 5.3 · Medium · EPSS 0.2%

Published
Updated

Stack: node

Affected products and versions

  • showdown

    Versions
    • ≥ 0, ≤ 2.1.0: Affected (semver)

    No fix published

  • showdown npm

    Affected ranges
    • SEMVER: ≤ 2.1.0

    No fix published

Original sources

Check your server →