What is CVE-2020-3839?

CVE-2020-3839 is a medium-severity vulnerability in Apple macOS, classified under Improper Input Validation. CVSS score: 5.5/10. Published 2020-02-27.

How severe is CVE-2020-3839?

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

Is CVE-2020-3839 known to be exploited?

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

Improper input validation in Apple macOS

CVE-2020-3839

A validation issue was addressed with improved input sanitization. This issue is fixed in macOS Catalina 10.15.3. An application may be able to read restricted memory.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

Published 2020-02-27 · last modified 2026-06-17.

CVSS v3 metric

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

EPSS exploit prediction

EPSS: 0.003 (25.6th percentile), scored 2026-10-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 25.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Apple macOS — versions unspecified
Apple Mac OS X

Weakness classification (CWE)

CWE-20 — Improper Input Validation

Public proof-of-concept exploits

ARPSyndicate/cvemon

References

support.apple.com/HT210919 (Release Notes, Vendor Advisory)

Frequently asked questions

What is CVE-2020-3839?: CVE-2020-3839 is a medium-severity vulnerability in Apple macOS, classified under Improper Input Validation. CVSS score: 5.5/10. Published 2020-02-27.
How severe is CVE-2020-3839?: Medium severity. CVSS v3 base score is 5.5 out of 10.
Is CVE-2020-3839 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.