What is CVE-2021-30658?

CVE-2021-30658 is a medium-severity vulnerability in Apple macOS, classified under Download of Code Without Integrity Check. CVSS score: 5.5/10. Published 2021-09-08.

How severe is CVE-2021-30658?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Vulnerability in Apple macOS

CVE-2021-30658

This issue was addressed with improved handling of file metadata. This issue is fixed in macOS Big Sur 11.3. A malicious application may bypass Gatekeeper checks.

Published 2021-09-08 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.004 (30.4th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 30th percentile — 30.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Apple macOS — versions unspecified

Weakness classification (CWE)

CWE-494 — Download of Code Without Integrity Check

References

support.apple.com/en-us/HT212325 (Vendor Advisory)

Frequently asked questions

What is CVE-2021-30658?: CVE-2021-30658 is a medium-severity vulnerability in Apple macOS, classified under Download of Code Without Integrity Check. CVSS score: 5.5/10. Published 2021-09-08.
How severe is CVE-2021-30658?: Medium severity. CVSS v3 base score is 5.5 out of 10.