CVE-2018-20784

Name: CVE-2018-20784
Creator: NVD / NIST
Published: 2019-02-22T15:29:00.237+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 4.17%

Last modified Jun 17, 2026

CVE-2018-20784 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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.. EPSS estimates a 4.17% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

4.17%

89.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-835

Affected Software

Vendor	Product	Versions	Update
Linux	Linux Kernel	>= 4.13, < 4.14.93	—
Linux	Linux Kernel	>= 4.19, < 4.19.15	—
Linux	Linux Kernel	>= 4.20, < 4.20.2	—
Linux	Linux Kernel	5.0	Rc1
Canonical	Ubuntu Linux	14.04	—
Canonical	Ubuntu Linux	16.04	—
Canonical	Ubuntu Linux	18.04	—
Redhat	Enterprise Linux	8.0	—
Redhat	Enterprise Linux For Real Time	8	—

References

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c40f7d74c741a907cfaeb73a7697081881c497d0Patch, Vendor Advisory
https://access.redhat.com/errata/RHSA-2019:1959Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:1971Third Party Advisory
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.20.2Release Notes, Vendor Advisory
https://github.com/torvalds/linux/commit/c40f7d74c741a907cfaeb73a7697081881c497d0Patch, Third Party Advisory
https://usn.ubuntu.com/4115-1/Third Party Advisory
https://usn.ubuntu.com/4118-1/Third Party Advisory
https://usn.ubuntu.com/4211-1/Third Party Advisory
https://usn.ubuntu.com/4211-2/Third Party Advisory
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c40f7d74c741a907cfaeb73a7697081881c497d0Patch, Vendor Advisory
https://access.redhat.com/errata/RHSA-2019:1959Third Party Advisory
https://access.redhat.com/errata/RHSA-2019:1971Third Party Advisory
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.20.2Release Notes, Vendor Advisory
https://github.com/torvalds/linux/commit/c40f7d74c741a907cfaeb73a7697081881c497d0Patch, Third Party Advisory
https://usn.ubuntu.com/4115-1/Third Party Advisory
https://usn.ubuntu.com/4118-1/Third Party Advisory
https://usn.ubuntu.com/4211-1/Third Party Advisory
https://usn.ubuntu.com/4211-2/Third Party Advisory

Timeline

Published: Feb 22, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2018-20784?

How severe is CVE-2018-20784?

CVE-2018-20784 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 4.17% probability of exploitation in the next 30 days.

How do I fix CVE-2018-20784?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2018-20784?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST