What is CVE-2019-8520?

CVE-2019-8520 is a medium-severity vulnerability in Apple macOS, classified under Out-of-bounds Read. CVSS score: 5.5/10. Published 2019-12-18.

How severe is CVE-2019-8520?

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

Out-of-bounds Read in Apple macOS

CVE-2019-8520

An out-of-bounds read was addressed with improved bounds checking. This issue is fixed in macOS Mojave 10.14.4. A malicious application may be able to read restricted memory.

Vulnerability class: Buffer Overflow

Published 2019-12-18 · 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 (22.0th percentile), scored 2026-10-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 22nd percentile — 22.0% 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-125 — Out-of-bounds Read

References

support.apple.com/HT209600 (Vendor Advisory)

Frequently asked questions

What is CVE-2019-8520?: CVE-2019-8520 is a medium-severity vulnerability in Apple macOS, classified under Out-of-bounds Read. CVSS score: 5.5/10. Published 2019-12-18.
How severe is CVE-2019-8520?: Medium severity. CVSS v3 base score is 5.5 out of 10.