What is the CVSS score of CVE-2026-33631?

CVE-2026-33631 has a CVSS 3.1 base score of 8.7 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L. EPSS exploitation probability: 0.0%.

Which versions of Apple are affected by CVE-2026-33631?

ClearanceKit 4.1 and earlier for macOS contains a file access control bypass that allows any local user to circumvent configured file access policies through seven unmonitored file operations,…. A patch is available.

How to fix or mitigate CVE-2026-33631?

Within 24 hours: inventory all macOS systems running ClearanceKit 4.1 or earlier and prioritize those handling sensitive data. Within 7 days: upgrade all affected instances to ClearanceKit 4.2 or later per vendor advisory (commit a3d1733 or later). Within 30 days: audit file access logs for signs of policy bypass exploitation during the vulnerable window, particularly rename and unlink operations that should have been denied.

Apple CVE-2026-33631

EUVD-2026-16371 HIGH

Missing Authorization (CWE-862)

2026-03-26 GitHub_M

Apple Authentication Bypass

8.7

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

8.7 HIGH

AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

Low

Lifecycle Timeline

Re-analysis Queued

Apr 20, 2026 - 20:37 vuln.today

cvss_changed

Analysis Updated

Apr 16, 2026 - 06:13 EUVD-patch-fix

executive_summary

Re-analysis Queued

Apr 16, 2026 - 05:29 backfill_euvd_patch

patch_released

Patch available

Apr 16, 2026 - 05:29 EUVD

4.2

EUVD ID Assigned

Mar 26, 2026 - 20:00 euvd

EUVD-2026-16371

Analysis Generated

Mar 26, 2026 - 20:00 vuln.today

CVE Published

Mar 26, 2026 - 19:30 nvd

HIGH 8.7

DescriptionGitHub Advisory

ClearanceKit intercepts file-system access events on macOS and enforces per-process access policies. In versions on the 4.1 branch and earlier, the opfilter Endpoint Security system extension enforced file access policy exclusively by intercepting ES_EVENT_TYPE_AUTH_OPEN events. Seven additional file operation event types were not intercepted, allowing any locally running process to bypass the configured FAA policy without triggering a denial. Commit a3d1733 adds subscriptions for all seven event types and routes them through the existing FAA policy evaluator. AUTH_RENAME and AUTH_UNLINK additionally preserve XProtect change detection: events on the XProtect path are allowed and trigger the existing onXProtectChanged callback rather than being evaluated against user policy. All versions on the 4.2 branch contain the fix. No known workarounds are available.

AnalysisAI

ClearanceKit 4.1 and earlier for macOS allows local authenticated users to completely bypass configured file access policies via seven unmonitored file operation event types. The opfilter Endpoint Security extension only intercepted ES_EVENT_TYPE_AUTH_OPEN events, enabling processes to perform rename, unlink, and five other file operations without policy enforcement or denial logging. Version 4.2 branch contains the fix via commit a3d1733. No public exploit identified at time of analysis, but exploitation requires only local access with low privileges (CVSS PR:L) and no special complexity.

Technical ContextAI

ClearanceKit is a macOS security tool implementing file access authorization (FAA) via an Endpoint Security system extension called opfilter. Endpoint Security is Apple's kernel-level framework for monitoring and authorizing system events. The affected product (cpe:2.3:a:craigjbass:clearancekit) suffers from CWE-862 (Missing Authorization), where the extension subscribed only to AUTH_OPEN events for file access control. Seven additional authorization event types (including AUTH_RENAME and AUTH_UNLINK explicitly mentioned in the advisory, plus five others) were left unmonitored, creating a fundamental gap in the enforcement architecture. Any process could invoke these unmonitored syscalls to access, modify, or delete files without triggering policy evaluation, effectively rendering the entire FAA framework ineffective for operations beyond file opening.

RemediationAI

Upgrade to any version on the ClearanceKit 4.2 branch, which contains the fix per the vendor advisory at https://github.com/craigjbass/clearancekit/security/advisories/GHSA-25f8-8cj2-m887. The fix implemented in commit a3d1733d2691a0d40209c48b01bf9291bf645207 adds subscriptions for all seven previously unmonitored event types and routes them through the existing FAA policy evaluator, while preserving XProtect change detection functionality for AUTH_RENAME and AUTH_UNLINK events. The vendor advisory explicitly states that no known workarounds are available, making upgrading to the 4.2 branch the only effective mitigation.