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CVE-2026-59711GHSA-CR32-G25G-VXJJ

showdown - Cross-Site Scripting via Unescaped Metadata Title in completeHTMLDocument

Published
Last modified
published
Not listed in CISA KEV
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: poc
  • Automatable: no
  • Technical impact: partial

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: poc · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • showdown showdown

    through 2.1.0

  • showdownnpm

    through 2.1.0

References 3

GitHub · showdownjs/showdown

vulncheck.com