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CVE-2026-59710GHSA-22G5-R2X5-97CX

showdown - Stored XSS via Unescaped Table Header ID Attribute Injection

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

Summary

showdown contains a stored cross-site scripting vulnerability in the parseHeaders function of src/subParsers/makehtml/tables.js that fails to properly escape table header ID attributes. Attackers can inject arbitrary HTML and script-executing SVG elements through double-quote characters in markdown table headers, achieving stored XSS when untrusted markdown is rendered with the default github flavor configuration.

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 4

GitHub · showdownjs/showdown

vulncheck.com