CVE-2021-20317: Medium severity Linux Linux kernel vulnerability

Q: What is the severity of CVE-2021-20317?

CVE-2021-20317 has a severity rating that indicates it could lead to a denial of service if exploited.

Q: How do I fix CVE-2021-20317?

To fix CVE-2021-20317, upgrade to the fixed kernel versions specified in the advisory for your distribution.

Q: What systems are affected by CVE-2021-20317?

CVE-2021-20317 affects multiple versions of the Linux kernel across different distributions, including Red Hat and Debian.

Q: Who can exploit CVE-2021-20317?

A local attacker with special user privileges can exploit CVE-2021-20317 to cause a denial of service.

Q: What kind of impact does CVE-2021-20317 have on systems?

CVE-2021-20317 can slow down and eventually stop the system, leading to significant operational disruptions.

Published Sep 17, 2021

Updated

A flaw was found in the Linux kernel. A corrupted timer tree caused the task wakeup to be missing in the timerqueueadd function in lib/timerqueue.c. This flaw allows a local attacker with special user privileges to cause a denial of service, slowing and eventually stopping the system while running OSP.

Other sources

A vulnerability was found due to a corrupted timer tree that caused a task wakeup to be missing in timerqueueadd in lib/timerqueue.c. This flaw may allow a local attacker with special user privilege to cause a denial of service problem, and system slowly dies while running OSP.

Upstream commit:

https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=511885d7061eda3eb1faf3f57dcc936ff75863f1

— Red Hat

Affected Software

12 affected componentsFixes available

redhat/kernel-rt<0:4.18.0-348.2.1.rt7.132.el8_5

0:4.18.0-348.2.1.rt7.132.el8_5

redhat/kernel<0:4.18.0-348.2.1.el8_5

0:4.18.0-348.2.1.el8_5

redhat/kernel-rt<0:4.18.0-193.70.1.rt13.120.el8_2

0:4.18.0-193.70.1.rt13.120.el8_2

redhat/kernel<0:4.18.0-193.70.1.el8_2

0:4.18.0-193.70.1.el8_2

redhat/kernel-rt<0:4.18.0-305.28.1.rt7.100.el8_4

0:4.18.0-305.28.1.rt7.100.el8_4

redhat/kernel<0:4.18.0-305.28.1.el8_4

0:4.18.0-305.28.1.el8_4

redhat/linux kernel<5.4

5.4

Linux Linux kernel<5.4

Linux Linux kernel=5.4

Debian Debian Linux=9.0

Debian Debian Linux=10.0

debian/linux

6.1.176-16.1.190-16.12.107-16.12.115-27.2.12-17.2.15-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade redhat/kernel-rt to a version that resolves this vulnerability.
Fixed in 0:4.18.0-348.2.1.rt7.132.el8_5
Upgrade
Upgrade redhat/kernel to a version that resolves this vulnerability.
Fixed in 0:4.18.0-348.2.1.el8_5
Upgrade
Upgrade redhat/kernel-rt to a version that resolves this vulnerability.
Fixed in 0:4.18.0-193.70.1.rt13.120.el8_2
Upgrade
Upgrade redhat/kernel to a version that resolves this vulnerability.
Fixed in 0:4.18.0-193.70.1.el8_2
Upgrade
Upgrade redhat/kernel-rt to a version that resolves this vulnerability.
Fixed in 0:4.18.0-305.28.1.rt7.100.el8_4
Upgrade
Upgrade redhat/kernel to a version that resolves this vulnerability.
Fixed in 0:4.18.0-305.28.1.el8_4
Upgrade
Upgrade redhat/Linux Kernel to a version that resolves this vulnerability.
Fixed in 5.4
Upgrade
Upgrade debian/linux to a version that resolves this vulnerability.
Fixed in 5.10.223-1Fixed in 5.10.234-1Fixed in 6.1.129-1Fixed in 6.1.135-1Fixed in 6.12.25-1Fixed in 6.12.27-1
Configuration
Load the kvm module with the pi_inject_timer=0 parameter to prevent the affected code path; use modprobe kvm pi_inject_timer=0, then modprobe kvm_intel.
Linux kernel KVM module pi_inject_timer = 0

Event History

Sep 23, 2021

CVE Published

04:20 PM

Event

04:20 PM

Sep 27, 2021

CVE Published

via MITRE·10:34 AM

Data Sourced

via MITRE·10:34 AM

DescriptionWeakness

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

What is the severity of CVE-2021-20317?