What is CVE-2026-40604?

CVE-2026-40604 is a medium-severity vulnerability in Apple macOS, classified under Protection Mechanism Failure. CVSS score: 4.4/10. Published 2026-04-21.

How severe is CVE-2026-40604?

Medium severity. CVSS v3 base score is 4.4 out of 10.

Vulnerability in Apple macOS

CVE-2026-40604

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.

EPSS: 0.001 (1.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H.

Affected products

Apple Macos
Craigjbass Clearancekit — versions < 5.0.6

Weakness classification (CWE)

CWE-693 — Protection Mechanism Failure

References

security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)

Frequently asked questions

What is CVE-2026-40604?: CVE-2026-40604 is a medium-severity vulnerability in Apple macOS, classified under Protection Mechanism Failure. CVSS score: 4.4/10. Published 2026-04-21.
How severe is CVE-2026-40604?: Medium severity. CVSS v3 base score is 4.4 out of 10.