What is CVE-2021-3747?

CVE-2021-3747 is a high-severity vulnerability in Apple macOS, classified under Incorrect Permission Assignment for Critical Resource. CVSS score: 8.8/10. Published 2021-10-01.

How severe is CVE-2021-3747?

High severity. CVSS v3 base score is 8.8 out of 10.

Is CVE-2021-3747 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Apple macOS

CVE-2021-3747

The MacOS version of Multipass, version 1.7.0, fixed in 1.7.2, accidentally installed the application directory with incorrect owner.

Published 2021-10-01 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.002 (14.2th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 14th percentile — 14.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000

Affected products

Apple macOS
Canonical Multipass — versions 1.7

Weakness classification (CWE)

CWE-732 — Incorrect Permission Assignment for Critical Resource

Public proof-of-concept exploits

ARPSyndicate/cvemon

References

github.com/canonical/multipass/issues/2261 (Patch, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2021-3747?: CVE-2021-3747 is a high-severity vulnerability in Apple macOS, classified under Incorrect Permission Assignment for Critical Resource. CVSS score: 8.8/10. Published 2021-10-01.
How severe is CVE-2021-3747?: High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2021-3747 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.