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UBUNTU-CVE-2021-20317 Moderate

UBUNTU-CVE-2021-20317

A flaw was found in the Linux kernel. A corrupted timer tree caused the task wakeup to be missing in the timerqueue_add 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.

Exploit probability Not scored
Published September 27, 2021
Required by Not available
Last source change August 18, 2026

02 / AFFECTED SOFTWARE

Affected packages

Ubuntu:18.04:LTS linux-oem

50 explicit affected versions

Ubuntu:18.04:LTS linux-aws-5.0

6 explicit affected versions

Ubuntu:20.04:LTS linux-raspi2

6 explicit affected versions

Ubuntu:Pro:20.04:LTS linux-azure-fde-5.15

57 explicit affected versions

Ubuntu:Pro:14.04:LTS linux

191 explicit affected versions

Ubuntu:18.04:LTS linux-aws

74 explicit affected versions

Ubuntu:18.04:LTS linux-oracle

54 explicit affected versions

Ubuntu:Pro:FIPS-updates:18.04:LTS linux-azure-fips

27 explicit affected versions

Ubuntu:18.04:LTS linux

86 explicit affected versions

Ubuntu:20.04:LTS linux-aws-5.8

4 explicit affected versions

Ubuntu:16.04:LTS linux-hwe-edge

23 explicit affected versions

Ubuntu:Pro:16.04:LTS linux-kvm

71 explicit affected versions

Ubuntu:Pro:FIPS:18.04:LTS linux-gcp-fips

1 explicit affected versions

Ubuntu:24.04:LTS linux-raspi-realtime

1 explicit affected versions

Ubuntu:18.04:LTS linux-oracle-5.0

7 explicit affected versions

Ubuntu:20.04:LTS linux-riscv

12 explicit affected versions

Ubuntu:22.04:LTS linux-intel-iot-realtime

1 explicit affected versions

Ubuntu:18.04:LTS linux-gcp-4.15

29 explicit affected versions

Ubuntu:18.04:LTS linux-hwe-edge

10 explicit affected versions

Ubuntu:Pro:16.04:LTS linux

137 explicit affected versions

Ubuntu:Pro:14.04:LTS linux-aws

70 explicit affected versions

Ubuntu:18.04:LTS linux-snapdragon

52 explicit affected versions

Ubuntu:Pro:FIPS:18.04:LTS linux-fips

1 explicit affected versions

Ubuntu:20.04:LTS linux-oem-5.6

29 explicit affected versions

Ubuntu:18.04:LTS linux-gcp-5.3

13 explicit affected versions

Ubuntu:18.04:LTS linux-kvm

68 explicit affected versions

Ubuntu:Pro:FIPS:18.04:LTS linux-azure-fips

1 explicit affected versions

Ubuntu:18.04:LTS linux-gke-4.15

33 explicit affected versions

Ubuntu:18.04:LTS linux-aws-5.3

10 explicit affected versions

Ubuntu:Pro:16.04:LTS linux-aws-hwe

53 explicit affected versions

Ubuntu:Nvidia-BlueField:24.04:LTS linux-bluefield

11 explicit affected versions

Ubuntu:Pro:16.04:LTS linux-gcp

76 explicit affected versions

Ubuntu:Pro:FIPS:16.04:LTS linux-fips

2 explicit affected versions

Ubuntu:18.04:LTS linux-raspi2

72 explicit affected versions

Ubuntu:18.04:LTS linux-azure-4.15

30 explicit affected versions

Ubuntu:Pro:FIPS:18.04:LTS linux-aws-fips

1 explicit affected versions

Ubuntu:Pro:FIPS-updates:18.04:LTS linux-fips

34 explicit affected versions

Ubuntu:20.04:LTS linux-oracle-5.8

5 explicit affected versions

Ubuntu:Pro:FIPS-updates:18.04:LTS linux-aws-fips

30 explicit affected versions

Ubuntu:20.04:LTS linux-riscv-5.8

10 explicit affected versions

Ubuntu:18.04:LTS linux-azure

44 explicit affected versions

Ubuntu:18.04:LTS linux-azure-5.3

16 explicit affected versions

Ubuntu:18.04:LTS linux-gcp

38 explicit affected versions

Ubuntu:18.04:LTS linux-oracle-5.3

9 explicit affected versions

Ubuntu:Pro:14.04:LTS linux-lts-xenial

114 explicit affected versions

Ubuntu:Pro:FIPS:16.04:LTS linux-fips

49 explicit affected versions

Ubuntu:Pro:16.04:LTS linux-azure

84 explicit affected versions

Ubuntu:Pro:14.04:LTS linux-azure

61 explicit affected versions

Ubuntu:20.04:LTS linux-gcp-5.8

4 explicit affected versions

Ubuntu:18.04:LTS linux-dell300x

18 explicit affected versions

Ubuntu:Pro:16.04:LTS linux-oracle

52 explicit affected versions

Ubuntu:18.04:LTS linux-hwe

43 explicit affected versions

Ubuntu:Pro:16.04:LTS linux-aws

92 explicit affected versions

Ubuntu:Pro:16.04:LTS linux-hwe

101 explicit affected versions

Ubuntu:18.04:LTS linux-gcp-edge

12 explicit affected versions

Ubuntu:18.04:LTS linux-azure-edge

4 explicit affected versions

Ubuntu:22.04:LTS linux-realtime

1 explicit affected versions

Ubuntu:Pro:FIPS-updates:18.04:LTS linux-gcp-fips

8 explicit affected versions

03 / CONNECTIONS

Connected vulnerabilities

04 / EVIDENCE

Source records

Open Source Vulnerabilities UBUNTU-CVE-2021-20317

A flaw was found in the Linux kernel. A corrupted timer tree caused the task wakeup to be missing in the timerqueue_add 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.

View original source

05 / REFERENCES

Further evidence