critical
CVE-2018-20784
kernel: infinite loop in update_blocked_averages() in kernel/sched/fair.c leading to denial of service
In the Trivy database since at least 24 Oct 2026, 07:11 UTCWhen it arrived before that build is not recorded.
Severity by source
NVD9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Red Hat5.9CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Trivy's own label is CRITICAL. Rated critical by NVD, Photon OS. Rated lower by Oracle (high), Red Hat (medium), Ubuntu (medium).
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.
Affected packages and fixed versions
| Source | Package | Fixed in |
|---|---|---|
| Photon OS 3.0 | linux, linux-aws, linux-esx and 1 more | 4.19.15-2.ph3 and 1 more |
| debian 11 | linux | 4.19.16-1 |
| debian 12 | linux | 4.19.16-1 |
| debian 13 | linux | 4.19.16-1 |
| debian 14 | linux | 4.19.16-1 |
| echo | linux | 4.19.16-1 |
| Oracle Linux 8 | bpftool, kernel, kernel-abi-whitelists and 17 more | 4.18.0-80.7.1.el8_0 |
| root.io debian 11 | rootio-linux | 4.19.16-1 |
| root.io debian 12 | rootio-linux | 4.19.16-1 |
| root.io debian 13 | rootio-linux | 4.19.16-1 |
| ubuntu 14.04-ESM | linux-aws, linux-azure, linux-lts-xenial | 4.4.0-1059.63 and 2 more |
| ubuntu 16.04 | linux, linux-aws, linux-aws-hwe and 8 more | 4.4.0-170.199 and 9 more |
Show all 81 entries from 17 sources
| Source | Package | Fixed in |
|---|---|---|
| Photon OS 3.0 | linux | 4.19.15-2.ph3 |
| Photon OS 3.0 | linux-aws | 4.19.15-1.ph3 |
| Photon OS 3.0 | linux-esx | 4.19.15-1.ph3 |
| Photon OS 3.0 | linux-secure | 4.19.15-1.ph3 |
| debian 11 | linux | 4.19.16-1 |
| debian 12 | linux | 4.19.16-1 |
| debian 13 | linux | 4.19.16-1 |
| debian 14 | linux | 4.19.16-1 |
| echo | linux | 4.19.16-1 |
| Oracle Linux 8 | bpftool | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-abi-whitelists | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-core | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-cross-headers | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-debug | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-debug-core | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-debug-devel | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-debug-modules | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-debug-modules-extra | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-devel | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-doc | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-headers | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-modules | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-modules-extra | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-tools | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-tools-libs | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | kernel-tools-libs-devel | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | perf | 4.18.0-80.7.1.el8_0 |
| Oracle Linux 8 | python3-perf | 4.18.0-80.7.1.el8_0 |
| root.io debian 11 | rootio-linux | 4.19.16-1 |
| root.io debian 12 | rootio-linux | 4.19.16-1 |
| root.io debian 13 | rootio-linux | 4.19.16-1 |
| ubuntu 14.04-ESM | linux-aws | 4.4.0-1059.63 |
| ubuntu 14.04-ESM | linux-azure | 4.15.0-1059.64~14.04.1 |
| ubuntu 14.04-ESM | linux-lts-xenial | 4.4.0-170.199~14.04.1 |
| ubuntu 16.04 | linux | 4.4.0-170.199 |
| ubuntu 16.04 | linux-aws | 4.4.0-1099.110 |
| ubuntu 16.04 | linux-aws-hwe | 4.15.0-1047.49~16.04.1 |
| ubuntu 16.04 | linux-azure | 4.15.0-1056.61 |
| ubuntu 16.04 | linux-gcp | 4.15.0-1041.43 |
| ubuntu 16.04 | linux-hwe | 4.15.0-60.67~16.04.1 |
| ubuntu 16.04 | linux-hwe-edge | 4.15.0-60.67~16.04.1 |
| ubuntu 16.04 | linux-kvm | 4.4.0-1063.70 |
| ubuntu 16.04 | linux-oracle | 4.15.0-1022.25~16.04.1 |
| ubuntu 16.04 | linux-raspi2 | 4.4.0-1126.135 |
| ubuntu 16.04 | linux-snapdragon | 4.4.0-1130.138 |
| ubuntu 16.04-ESM | linux | 4.4.0-170.199 |
| ubuntu 16.04-ESM | linux-aws | 4.4.0-1099.110 |
| ubuntu 16.04-ESM | linux-aws-hwe | 4.15.0-1047.49~16.04.1 |
| ubuntu 16.04-ESM | linux-azure | 4.15.0-1056.61 |
| ubuntu 16.04-ESM | linux-gcp | 4.15.0-1041.43 |
| ubuntu 16.04-ESM | linux-hwe | 4.15.0-60.67~16.04.1 |
| ubuntu 16.04-ESM | linux-hwe-edge | 4.15.0-60.67~16.04.1 |
| ubuntu 16.04-ESM | linux-kvm | 4.4.0-1063.70 |
| ubuntu 16.04-ESM | linux-oracle | 4.15.0-1022.25~16.04.1 |
| ubuntu 18.04 | linux | 4.15.0-60.67 |
| ubuntu 18.04 | linux-aws | 4.15.0-1047.49 |
| ubuntu 18.04 | linux-azure | 5.0.0-1014.14~18.04.1 |
| ubuntu 18.04 | linux-azure-edge | 5.0.0-1014.14~18.04.1 |
| ubuntu 18.04 | linux-gcp | 4.15.0-1042.45 |
| ubuntu 18.04 | linux-gcp-edge | 4.15.0-1042.45 |
| ubuntu 18.04 | linux-gke-4.15 | 4.15.0-1041.43 |
| ubuntu 18.04 | linux-hwe | 5.0.0-23.24~18.04.1 |
| ubuntu 18.04 | linux-kvm | 4.15.0-1043.43 |
| ubuntu 18.04 | linux-oem | 4.15.0-1056.65 |
| ubuntu 18.04 | linux-oracle | 4.15.0-1022.25 |
| ubuntu 18.04 | linux-raspi2 | 4.15.0-1044.47 |
| ubuntu 18.04 | linux-snapdragon | 4.15.0-1062.69 |
| ubuntu 18.04-ESM | linux | 4.15.0-60.67 |
| ubuntu 18.04-ESM | linux-aws | 4.15.0-1047.49 |
| ubuntu 18.04-ESM | linux-azure | 5.0.0-1014.14~18.04.1 |
| ubuntu 18.04-ESM | linux-azure-edge | 5.0.0-1014.14~18.04.1 |
| ubuntu 18.04-ESM | linux-gcp | 4.15.0-1042.45 |
| ubuntu 18.04-ESM | linux-gcp-edge | 4.15.0-1042.45 |
| ubuntu 18.04-ESM | linux-gke-4.15 | 4.15.0-1041.43 |
| ubuntu 18.04-ESM | linux-hwe | 5.0.0-23.24~18.04.1 |
| ubuntu 18.04-ESM | linux-kvm | 4.15.0-1043.43 |
| ubuntu 18.04-ESM | linux-oem | 4.15.0-1056.65 |
| ubuntu 18.04-ESM | linux-oracle | 4.15.0-1022.25 |
| ubuntu 19.04 | linux-oracle | 5.0.0-1004.8 |
| ubuntu 19.10 | linux-oem | 4.15.0-1059.68 |
References
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c40f7d74c741a907cfaeb73a7697081881c497d0
- https://access.redhat.com/errata/RHSA-2019:1959
- https://access.redhat.com/errata/RHSA-2019:1971
- https://access.redhat.com/security/cve/CVE-2018-20784
- https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.20.2
- https://git.kernel.org/linus/c40f7d74c741a907cfaeb73a7697081881c497d0
- https://github.com/torvalds/linux/commit/c40f7d74c741a907cfaeb73a7697081881c497d0
- https://linux.oracle.com/cve/CVE-2018-20784.html
All 19 references
- https://linux.oracle.com/errata/ELSA-2019-1959.html
- https://nvd.nist.gov/vuln/detail/CVE-2018-20784
- https://ubuntu.com/security/notices/USN-4115-1
- https://ubuntu.com/security/notices/USN-4118-1
- https://ubuntu.com/security/notices/USN-4211-1
- https://ubuntu.com/security/notices/USN-4211-2
- https://usn.ubuntu.com/4115-1/
- https://usn.ubuntu.com/4118-1/
- https://usn.ubuntu.com/4211-1/
- https://usn.ubuntu.com/4211-2/
- https://www.cve.org/CVERecord?id=CVE-2018-20784