CVE-2018-20784: Canonical Ubuntu Linux

Critical severity, CVSS 9.8. EPSS: 4.2% chance of exploitation in the next 30 days.

In the Linux kernel before 4.20.2, kernel/sched/fair.c mishandles leaf cfs_rq's, which allows attackers to cause a denial of service (infinite loop in update_blocked_averages) or possibly have unspecified other impact by inducing a high load.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 18.04 only
• Linux Linux Kernel: from 4.13, before 4.14.93 (fixed in 4.14.93); from 4.19, before 4.19.15 (fixed in 4.19.15); from 4.20, before 4.20.2 (fixed in 4.20.2); version 5.0 only
• Red Hat Enterprise Linux: version 8.0 only
• Red Hat Enterprise Linux For Real Time: version 8 only

Published 2019-02-22. Last modified 2026-06-17.