Vulnerability Name:

CVE-2018-20784 (CCN-158009)

Assigned:2018-12-28
Published:2018-12-28
Updated:2021-06-02
Summary: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.
CVSS v3 Severity:9.8 Critical (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)
8.5 High (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): High
Availibility (A): High
4.0 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
3.5 Low (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Low
5.9 Medium (REDHAT CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H)
5.2 Medium (REDHAT Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
CVSS v2 Severity:7.5 High (CVSS v2 Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Authentication (Au): None
Impact Metrics:Confidentiality (C): Partial
Integrity (I): Partial
Availibility (A): Partial
2.1 Low (CCN CVSS v2 Vector: AV:L/AC:L/Au:N/C:N/I:N/A:P)
Exploitability Metrics:Access Vector (AV): Local
Access Complexity (AC): Low
Athentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Partial
Vulnerability Type:CWE-835
Vulnerability Consequences:Denial of Service
References:Source: MITRE
Type: CNA
CVE-2018-20784

Source: MISC
Type: Patch, Vendor Advisory
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c40f7d74c741a907cfaeb73a7697081881c497d0

Source: REDHAT
Type: Third Party Advisory
RHSA-2019:1959

Source: REDHAT
Type: Third Party Advisory
RHSA-2019:1971

Source: MISC
Type: Release Notes, Vendor Advisory
https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.20.2

Source: XF
Type: UNKNOWN
linux-kernel-cve201820784-dos(158009)

Source: CCN
Type: Linux Kernel GIT Repository
sched/fair: Fix infinite loop in update_blocked_averages() by reverting a9e7f6544b9c

Source: MISC
Type: Patch, Third Party Advisory
https://github.com/torvalds/linux/commit/c40f7d74c741a907cfaeb73a7697081881c497d0

Source: UBUNTU
Type: Third Party Advisory
USN-4115-1

Source: UBUNTU
Type: Third Party Advisory
USN-4118-1

Source: UBUNTU
Type: Third Party Advisory
USN-4211-1

Source: UBUNTU
Type: Third Party Advisory
USN-4211-2

Source: CCN
Type: WhiteSource Vulnerability Database
CVE-2018-20784

Vulnerable Configuration:Configuration 1:
  • cpe:/o:linux:linux_kernel:*:*:*:*:*:*:*:* (Version >= 4.13 and < 4.14.93)
  • OR cpe:/o:linux:linux_kernel:*:*:*:*:*:*:*:* (Version >= 4.19 and < 4.19.15)
  • OR cpe:/o:linux:linux_kernel:*:*:*:*:*:*:*:* (Version >= 4.20 and < 4.20.2)
  • OR cpe:/o:linux:linux_kernel:5.0:rc1:*:*:*:*:*:*

    • Configuration 2:
  • cpe:/o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:*
  • OR cpe:/o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*
  • OR cpe:/o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*

    • Configuration 3:
  • cpe:/o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
  • OR cpe:/o:redhat:enterprise_linux_for_real_time:8:*:*:*:*:*:*:*

    • Configuration RedHat 1:
  • cpe:/a:redhat:enterprise_linux:8:*:*:*:*:*:*:*

    • Configuration RedHat 2:
  • cpe:/a:redhat:enterprise_linux:8::crb:*:*:*:*:*

    • Configuration RedHat 3:
  • cpe:/o:redhat:enterprise_linux:8:*:*:*:*:*:*:*

    • Configuration RedHat 4:
  • cpe:/o:redhat:enterprise_linux:8::baseos:*:*:*:*:*

    • Configuration RedHat 5:
  • cpe:/a:redhat:enterprise_linux:8::nfv:*:*:*:*:*

    • Configuration RedHat 6:
  • cpe:/a:redhat:enterprise_linux:8::realtime:*:*:*:*:*

    • Configuration CCN 1:
  • cpe:/o:linux:linux_kernel:4.20.1:*:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    Oval Definitions
    Definition IDClassTitleLast Modified
    oval:com.redhat.rhsa:def:20191959
    P
    		RHSA-2019:1959: kernel security, bug fix, and enhancement update (Important)
    2019-07-30
    oval:com.redhat.rhsa:def:20191971
    P
    		RHSA-2019:1971: kernel-rt security and bug fix update (Important)
    2019-07-30
    oval:com.ubuntu.bionic:def:201820784000
    V
    		CVE-2018-20784 on Ubuntu 18.04 LTS (bionic) - medium.
    2019-02-22
    oval:com.ubuntu.cosmic:def:2018207840000000
    V
    		CVE-2018-20784 on Ubuntu 18.10 (cosmic) - medium.
    2019-02-22
    oval:com.ubuntu.cosmic:def:201820784000
    V
    		CVE-2018-20784 on Ubuntu 18.10 (cosmic) - medium.
    2019-02-22
    oval:com.ubuntu.bionic:def:2018207840000000
    V
    		CVE-2018-20784 on Ubuntu 18.04 LTS (bionic) - medium.
    2019-02-22
    oval:com.ubuntu.disco:def:2018207840000000
    V
    		CVE-2018-20784 on Ubuntu 19.04 (disco) - medium.
    2019-02-22
    oval:com.ubuntu.trusty:def:201820784000
    V
    		CVE-2018-20784 on Ubuntu 14.04 LTS (trusty) - medium.
    2019-02-22
    oval:com.ubuntu.xenial:def:2018207840000000
    V
    		CVE-2018-20784 on Ubuntu 16.04 LTS (xenial) - medium.
    2019-02-22
    oval:com.ubuntu.xenial:def:201820784000
    V
    		CVE-2018-20784 on Ubuntu 16.04 LTS (xenial) - medium.
    2019-02-22
    BACK
    linux linux kernel *
    linux linux kernel *
    linux linux kernel *
    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
    linux linux kernel 4.20.1