CVE-2026-59711
mediumpriority · track · 0EPSS 0.002 · 14 %ileEUUSEPSS · scored 2026-10-27
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 1.3–6.1
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (2)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- GHSA-cr32-g25g-vxjjshowdown metadata title handling allows cross-site scripting2026-07-06ghsa · osvUS
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.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (9)
External citations — patches, advisories, analysis.
- https://github.com/showdownjs/showdowncnnvd
- https://github.com/showdownjs/showdown/issues/1047cnnvd
- https://www.vulncheck.com/advisories/showdown-cross-site-scripting-via-unescaped-metadata-title-in-completehtmldocumentcnnvd
- https://github.com/showdownjs/showdownenisa_euvd
- https://github.com/showdownjs/showdown/issues/1047enisa_euvd
- https://www.vulncheck.com/advisories/showdown-cross-site-scripting-via-unescaped-metadata-title-in-completehtmldocumentenisa_euvd
- https://github.com/showdownjs/showdownnvd
- https://github.com/showdownjs/showdown/issues/1047nvd
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