What is CVE-2021-30833?

CVE-2021-30833 is a medium-severity vulnerability in Apple macOS. CVSS score: 5.5/10. Published 2021-10-28.

How severe is CVE-2021-30833?

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

Is CVE-2021-30833 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-2021-30833

This issue was addressed with improved checks. This issue is fixed in macOS Monterey 12.0.1. Unpacking a maliciously crafted archive may allow an attacker to write arbitrary files.

Published 2021-10-28 · 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: 0.427 (98.7th percentile), scored 2026-10-02.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 99th percentile — 98.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.427 · newest: 0.427 · change: 0.000

Affected products

Apple macOS — versions unspecified
Apple Mac OS X — versions 10.15.7

Public proof-of-concept exploits

houjingyi233/macOS-iOS-system-security

References

support.apple.com/kb/HT212871 (Vendor Advisory)
support.apple.com/kb/HT212872 (Vendor Advisory)
support.apple.com/en-us/HT212869 (Vendor Advisory)

Frequently asked questions

What is CVE-2021-30833?: CVE-2021-30833 is a medium-severity vulnerability in Apple macOS. CVSS score: 5.5/10. Published 2021-10-28.
How severe is CVE-2021-30833?: Medium severity. CVSS v3 base score is 5.5 out of 10.
Is CVE-2021-30833 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.