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UBUNTU-CVE-2021-20321 Moderate

UBUNTU-CVE-2021-20321

A race condition accessing file object in the Linux kernel OverlayFS subsystem was found in the way users do rename in specific way with OverlayFS. A local user could use this flaw to crash the system.

Exploit probability Not scored
Published October 18, 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-aws-5.11

8 explicit affected versions

Ubuntu:20.04:LTS linux-raspi2

6 explicit affected versions

Ubuntu:Pro:FIPS-updates:20.04:LTS linux-fips

9 explicit affected versions

Ubuntu:Pro:14.04:LTS linux

191 explicit affected versions

Ubuntu:18.04:LTS linux-aws

74 explicit affected versions

Ubuntu:20.04:LTS linux-kvm

35 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:20.04:LTS linux-oem-5.14

2 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

86 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:20.04:LTS linux-hwe-5.8

21 explicit affected versions

Ubuntu:20.04:LTS linux-hwe-5.13

2 explicit affected versions

Ubuntu:Pro:FIPS-updates:20.04:LTS linux-aws-fips

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:20.04:LTS linux-gcp-5.11

8 explicit affected versions

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

1 explicit affected versions

Ubuntu:20.04:LTS linux-intel-5.13

7 explicit affected versions

Ubuntu:20.04:LTS linux-oem-5.13

9 explicit affected versions

Ubuntu:20.04:LTS linux-gcp

38 explicit affected versions

Ubuntu:20.04:LTS linux

46 explicit affected versions

Ubuntu:20.04:LTS linux-oracle-5.11

8 explicit affected versions

Ubuntu:20.04:LTS linux-azure

38 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

152 explicit affected versions

Ubuntu:18.04:LTS linux-gke-5.4

22 explicit affected versions

Ubuntu:Pro:14.04:LTS linux-aws

85 explicit affected versions

Ubuntu:18.04:LTS linux-snapdragon

52 explicit affected versions

Ubuntu:Pro:FIPS:20.04:LTS linux-aws-fips

1 explicit affected versions

Ubuntu:20.04:LTS linux-oem-5.10

21 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:20.04:LTS linux-aws

40 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:20.04:LTS linux-hwe-5.11

10 explicit affected versions

Ubuntu:Pro:16.04:LTS linux-gcp

76 explicit affected versions

Ubuntu:20.04:LTS linux-azure-5.8

7 explicit affected versions

Ubuntu:20.04:LTS linux-oracle

38 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-hwe-5.4

34 explicit affected versions

Ubuntu:Pro:FIPS:20.04:LTS linux-azure-fips

1 explicit affected versions

Ubuntu:20.04:LTS linux-ibm

6 explicit affected versions

Ubuntu:20.04:LTS linux-gke

17 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:20.04:LTS linux-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:18.04:LTS linux-gcp-5.4

28 explicit affected versions

Ubuntu:Pro:FIPS:20.04:LTS linux-gcp-fips

1 explicit affected versions

Ubuntu:18.04:LTS linux-aws-5.4

28 explicit affected versions

Ubuntu:20.04:LTS linux-azure-5.11

9 explicit affected versions

Ubuntu:Pro:FIPS-updates:20.04:LTS linux-azure-fips

1 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-raspi-5.4

26 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:20.04:LTS linux-riscv-5.11

7 explicit affected versions

Ubuntu:18.04:LTS linux-gkeop-5.4

22 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

129 explicit affected versions

Ubuntu:18.04:LTS linux-oracle-5.4

28 explicit affected versions

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

63 explicit affected versions

Ubuntu:20.04:LTS linux-bluefield

9 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-azure-5.4

28 explicit affected versions

Ubuntu:18.04:LTS linux-hwe

43 explicit affected versions

Ubuntu:Pro:FIPS-updates:20.04:LTS linux-gcp-fips

1 explicit affected versions

Ubuntu:Pro:16.04:LTS linux-aws

108 explicit affected versions

Ubuntu:Pro:16.04:LTS linux-hwe

101 explicit affected versions

Ubuntu:20.04:LTS linux-raspi

30 explicit affected versions

Ubuntu:18.04:LTS linux-azure-edge

4 explicit affected versions

Ubuntu:20.04:LTS linux-gkeop

17 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-2021-20321

A race condition accessing file object in the Linux kernel OverlayFS subsystem was found in the way users do rename in specific way with OverlayFS. A local user could use this flaw to crash the system.

View original source

05 / REFERENCES

Further evidence