showdown metadata title handling allows cross-site scripting
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.
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describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-59711US | — | — | ||
showdown contains a cross-site scripting vulnerability in metadata title handling that allows attackers to inject arbitrary HTML and JavaScript. When completeHTMLDocument option is… | ||||
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references
External citations — patches, advisories, analysis.
- https://github.com/showdownjs/showdownPACKAGE
- https://github.com/showdownjs/showdown/commit/184a3e4e97f90e075c4512f2c4c06dcf655e91b7WEB
- https://github.com/showdownjs/showdown/issues/1047WEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-59711ADVISORY
- https://www.vulncheck.com/advisories/showdown-cross-site-scripting-via-unescaped-metadata-title-in-completehtmldocumentWEB
scry
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