CVE-2015-5879: Apple iPhone OS

Medium severity, CVSS 5.0. EPSS: 2.4% chance of exploitation in the next 30 days.

XNU in the kernel in Apple iOS before 9 does not properly validate the headers of TCP packets, which allows remote attackers to bypass the sequence-number protection mechanism and cause a denial of service (TCP connection disruption) via a crafted header.

Affected products

• Apple iPhone OS: up to and including 8.4.1
• Apple Mac OS X: up to and including 10.10.5

Published 2015-09-18. Last modified 2026-06-17.