CVE-2026-59710
mediumpriority · track · 0EPSS 0.003 · 27 %ileEUUSEPSS · scored 2026-10-27
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.
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-22g5-r2x5-97cxshowdown allows stored cross-site scripting through table header ID injection2026-07-07ghsa · osvUS
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.
also known as (3)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (12)
External citations — patches, advisories, analysis.
- https://github.com/showdownjs/showdowncnnvd
- https://github.com/showdownjs/showdown/commit/e5cab1e9a5dcea2bb3cbf888863fa7e65ab37edfcnnvd
- https://github.com/showdownjs/showdown/issues/1046cnnvd
- https://www.vulncheck.com/advisories/showdown-stored-xss-via-unescaped-table-header-id-attribute-injectioncnnvd
- https://github.com/showdownjs/showdownenisa_euvd
- https://github.com/showdownjs/showdown/commit/e5cab1e9a5dcea2bb3cbf888863fa7e65ab37edfenisa_euvd
- https://github.com/showdownjs/showdown/issues/1046enisa_euvd
- https://www.vulncheck.com/advisories/showdown-stored-xss-via-unescaped-table-header-id-attribute-injectionenisa_euvd
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