SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2018-4398

An issue existed in the method for determining prime numbers.

HIGH 7.5EPSS 1.63%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.63%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

An issue existed in the method for determining prime numbers. This issue was addressed by using pseudorandom bases for testing of primes. This issue affected versions prior to iOS 12.1, macOS Mojave 10.14.1, tvOS 12.1, watchOS 5.1, iTunes 12.9.1, iCloud for Windows 7.8.

CVSS 3.0
7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS
1.63% probability · 76th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-20
Affected
apple/iphone os · apple/mac os x · apple/tvos · apple/watchos · apple/icloud · apple/itunes
Source
product-security@apple.com
EPSS trend
0%3%5%27 October 2026: 1.63%27 October 202627 October 2026

EPSS 1.6% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.