What is CVE-2019-8634?

CVE-2019-8634 is a high-severity vulnerability in Apple macOS, classified under Improper Authentication. CVSS score: 8.8/10. Published 2019-12-18.

How severe is CVE-2019-8634?

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

Auth bypass in Apple macOS

CVE-2019-8634

An authentication issue was addressed with improved state management. This issue is fixed in macOS Mojave 10.14.5. A user may be unexpectedly logged in to another user’s account.

Vulnerability class: Broken Authentication

Published 2019-12-18 · last modified 2026-06-17.

CVSS v3 metric

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

EPSS exploit prediction

EPSS: 0.010 (61.0th percentile), scored 2026-10-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 61st percentile — 61.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000

Affected products

Apple macOS — versions unspecified
Apple Mac OS X — versions 10.12.6, 10.13.6

Weakness classification (CWE)

CWE-287 — Improper Authentication

References

support.apple.com/HT210119 (Vendor Advisory)

Frequently asked questions

What is CVE-2019-8634?: CVE-2019-8634 is a high-severity vulnerability in Apple macOS, classified under Improper Authentication. CVSS score: 8.8/10. Published 2019-12-18.
How severe is CVE-2019-8634?: High severity. CVSS v3 base score is 8.8 out of 10.