What is CVE-2018-4339?

CVE-2018-4339 is a medium-severity vulnerability in Apple iOS. CVSS score: 5.5/10. Published 2020-10-27.

How severe is CVE-2018-4339?

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

Vulnerability in Apple iOS

CVE-2018-4339

This issue was addressed with a new entitlement. This issue is fixed in iOS 12.1. A local user may be able to read a persistent device identifier.

Published 2020-10-27 · 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 (17.1th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 17th percentile — 17.1% 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 iOS — versions unspecified
Apple Iphone OS

References

support.apple.com/en-us/HT209192 (Vendor Advisory)

Frequently asked questions

What is CVE-2018-4339?: CVE-2018-4339 is a medium-severity vulnerability in Apple iOS. CVSS score: 5.5/10. Published 2020-10-27.
How severe is CVE-2018-4339?: Medium severity. CVSS v3 base score is 5.5 out of 10.