{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-59711", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-07-06T15:31:46.188Z", "datePublished": "2026-07-06T21:00:38.491Z", "dateUpdated": "2026-07-06T21:00:38.491Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-07-06T21:00:38.491Z"}, "title": "showdown - Cross-Site Scripting via Unescaped Metadata Title in completeHTMLDocument", "descriptions": [{"lang": "en", "value": "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."}], "datePublic": "2026-03-12T00:00:00.000Z", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-79", "description": "Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')", "type": "CWE"}]}], "affected": [{"vendor": "showdown", "product": "showdown", "defaultStatus": "unaffected", "packageURL": "pkg:npm/showdown", "versions": [{"version": "0", "status": "affected", "versionType": "semver", "lessThanOrEqual": "2.1.0"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:showdownjs:showdown:*:*:*:*:*:node.js:*:*", "versionEndExcluding": "*"}]}]}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "LOW", "subConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "subIntegrityImpact": "LOW", "vulnAvailabilityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "version": "4.0", "baseSeverity": "MEDIUM", "baseScore": 5.3, "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N"}}, {"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV3_1": {"attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE", "version": "3.1", "baseSeverity": "MEDIUM", "baseScore": 6.1, "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"}}], "references": [{"url": "https://github.com/showdownjs/showdown/issues/1047", "name": "Pull Request", "tags": ["issue-tracking"]}, {"url": "https://github.com/showdownjs/showdown", "name": "Product", "tags": ["product"]}, {"url": "https://www.vulncheck.com/advisories/showdown-cross-site-scripting-via-unescaped-metadata-title-in-completehtmldocument", "tags": ["third-party-advisory"]}], "credits": [{"lang": "en", "value": "vc-smoore", "type": "reporter"}], "x_generator": {"engine": "vulncheck-endgame"}}}}

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