CVE-2021-47668: can: dev: can_restart: fix use after free bug

Q: What is the severity of CVE-2021-47668?

CVE-2021-47668 has been classified with a moderate severity level due to the potential for a use-after-free condition in the Linux kernel.

Q: How do I fix CVE-2021-47668?

To fix CVE-2021-47668, you should update to the latest version of the Linux kernel that includes the patch addressing this vulnerability.

Q: Which versions of the Linux kernel are affected by CVE-2021-47668?

CVE-2021-47668 affects multiple versions of the Linux kernel prior to the application of the relevant patches.

Q: What is a use-after-free bug in the context of CVE-2021-47668?

In CVE-2021-47668, a use-after-free bug occurs when the memory of a data structure is accessed after it has been freed, potentially leading to memory corruption.

Q: Can CVE-2021-47668 be exploited remotely?

Yes, an attacker with appropriate privileges could potentially exploit CVE-2021-47668, but remote exploitation is contingent on specific conditions being met.

Published Apr 17, 2025

Updated

In the Linux kernel, the following vulnerability has been resolved:

can: dev: canrestart: fix use after free bug

After calling netifrxni(skb), dereferencing skb is unsafe. Especially, the canframe cf which aliases skb memory is accessed after the netifrxni() in: stats->rxbytes += cf->len;

Reordering the lines solves the issue.

Affected Software

137 affected componentsFixes available

Linux Linux kernel

Linux Linux kernel>=2.6.31<4.4.254

Linux Linux kernel>=4.5<4.9.254

Linux Linux kernel>=4.10<4.14.218

Linux Linux kernel>=4.15<4.19.171

Linux Linux kernel>=4.20<5.4.93

Linux Linux kernel>=5.5<5.10.11

Linux Linux kernel=5.11-rc1

Linux Linux kernel=5.11-rc2

Linux Linux kernel=5.11-rc3

Linux Linux kernel=5.11-rc4

ubuntu/linux-aws<4.4.0-1087.91

4.4.0-1087.91

ubuntu/linux-azure<4.15.0-1112.124~14.04.1

4.15.0-1112.124~14.04.1

ubuntu/linux-lts-xenial<4.4.0-204.236~14.04.1

4.4.0-204.236~14.04.1

ubuntu/linux*

ubuntu/linux<4.4.0-204.236

4.4.0-204.236

ubuntu/linux-aws<4.4.0-1123.137

4.4.0-1123.137

ubuntu/linux-aws-hwe<4.15.0-1098.105~16.04.1

4.15.0-1098.105~16.04.1

ubuntu/linux-azure<4.15.0-1112.124~16.04.1

4.15.0-1112.124~16.04.1

ubuntu/linux-gcp<4.15.0-1097.110~16.04.1

4.15.0-1097.110~16.04.1

ubuntu/linux-hwe<4.15.0-142.146~16.04.1

4.15.0-142.146~16.04.1

ubuntu/linux-kvm<4.4.0-1089.98

4.4.0-1089.98

ubuntu/linux-oracle<4.15.0-1069.77~16.04.1

4.15.0-1069.77~16.04.1

ubuntu/linux-hwe-edge*

ubuntu/linux-fips<4.4.0-1057.63

4.4.0-1057.63

ubuntu/linux-fips*

ubuntu/linux<4.15.0-141.145

4.15.0-141.145

ubuntu/linux-aws<4.15.0-1098.105

4.15.0-1098.105

ubuntu/linux-aws-5.4<5.4.0-1039.41~18.04.1

5.4.0-1039.41~18.04.1

ubuntu/linux-azure-4.15<4.15.0-1112.125

4.15.0-1112.125

ubuntu/linux-azure-5.4<5.4.0-1041.43~18.04.1

5.4.0-1041.43~18.04.1

ubuntu/linux-gcp-4.15<4.15.0-1097.110

4.15.0-1097.110

ubuntu/linux-gcp-5.4<5.4.0-1038.41~18.04.1

5.4.0-1038.41~18.04.1

ubuntu/linux-hwe-5.4<5.4.0-67.75~18.04.1

5.4.0-67.75~18.04.1

ubuntu/linux-kvm<4.15.0-1089.91

4.15.0-1089.91

ubuntu/linux-oracle<4.15.0-1069.77

4.15.0-1069.77

ubuntu/linux-oracle-5.4<5.4.0-1039.42~18.04.1

5.4.0-1039.42~18.04.1

ubuntu/linux-raspi-5.4<5.4.0-1030.33~18.04.1

5.4.0-1030.33~18.04.1

ubuntu/linux-aws-5.0*

ubuntu/linux-aws-5.3*

ubuntu/linux-azure*

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.3*

ubuntu/linux-gke-4.15*

ubuntu/linux-gke-5.4*

ubuntu/linux-gkeop-5.4*

ubuntu/linux-hwe*

ubuntu/linux-hwe-edge*

ubuntu/linux-oem*

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-aws-fips<4.15.0-2041.43

4.15.0-2041.43

ubuntu/linux-azure-fips<4.15.0-2024.27

4.15.0-2024.27

ubuntu/linux-fips<4.15.0-1057.65

4.15.0-1057.65

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux<5.4.0-67.75

5.4.0-67.75

ubuntu/linux-aws<5.4.0-1039.41

5.4.0-1039.41

ubuntu/linux-azure<5.4.0-1041.43

5.4.0-1041.43

ubuntu/linux-gcp<5.4.0-1038.41

5.4.0-1038.41

ubuntu/linux-kvm<5.4.0-1034.35

5.4.0-1034.35

ubuntu/linux-oracle<5.4.0-1039.42

5.4.0-1039.42

ubuntu/linux-raspi<5.4.0-1030.33

5.4.0-1030.33

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.8*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

ubuntu/linux-gcp-5.11*

ubuntu/linux-gcp-5.13*

ubuntu/linux-gcp-5.8*

ubuntu/linux-gke*

ubuntu/linux-gke-5.15*

ubuntu/linux-gkeop*

ubuntu/linux-gkeop-5.15*

ubuntu/linux-hwe-5.11*

ubuntu/linux-hwe-5.13*

ubuntu/linux-hwe-5.8*

ubuntu/linux-intel-5.13*

ubuntu/linux-oem-5.10*

ubuntu/linux-oem-5.13*

ubuntu/linux-oem-5.6*

ubuntu/linux-oracle-5.11*

ubuntu/linux-oracle-5.13*

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.8*

ubuntu/linux-aws-fips<5.4.0-1069.73+fips2

5.4.0-1069.73+fips2

ubuntu/linux-azure-fips<5.4.0-1073.76+fips1

5.4.0-1073.76+fips1

ubuntu/linux-gcp-fips<5.4.0-1067.71~20.04.1

5.4.0-1067.71~20.04.1

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-aws-6.5*

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-lowlatency-hwe-6.5*

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-oem-6.5*

ubuntu/linux-oracle-6.5*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-vmware*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 4.4.0-1087.91
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 4.15.0-1112.124~14.04.1
Upgrade
Upgrade ubuntu/linux-lts-xenial to a version that resolves this vulnerability.
Fixed in 4.4.0-204.236~14.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 4.4.0-204.236
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 4.4.0-1123.137
Upgrade
Upgrade ubuntu/linux-aws-hwe to a version that resolves this vulnerability.
Fixed in 4.15.0-1098.105~16.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 4.15.0-1112.124~16.04.1
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 4.15.0-1097.110~16.04.1
Upgrade
Upgrade ubuntu/linux-hwe to a version that resolves this vulnerability.
Fixed in 4.15.0-142.146~16.04.1
Upgrade
Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 4.4.0-1089.98
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 4.15.0-1069.77~16.04.1
Upgrade
Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 4.4.0-1057.63
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 4.15.0-141.145
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 4.15.0-1098.105
Upgrade
Upgrade ubuntu/linux-aws-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1039.41~18.04.1
Upgrade
Upgrade ubuntu/linux-azure-4.15 to a version that resolves this vulnerability.
Fixed in 4.15.0-1112.125
Upgrade
Upgrade ubuntu/linux-azure-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1041.43~18.04.1
Upgrade
Upgrade ubuntu/linux-gcp-4.15 to a version that resolves this vulnerability.
Fixed in 4.15.0-1097.110
Upgrade
Upgrade ubuntu/linux-gcp-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1038.41~18.04.1
Upgrade
Upgrade ubuntu/linux-hwe-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-67.75~18.04.1
Upgrade
Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 4.15.0-1089.91
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 4.15.0-1069.77
Upgrade
Upgrade ubuntu/linux-oracle-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1039.42~18.04.1
Upgrade
Upgrade ubuntu/linux-raspi-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1030.33~18.04.1
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 4.15.0-2041.43
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 4.15.0-2024.27
Upgrade
Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 4.15.0-1057.65
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 5.4.0-67.75
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 5.4.0-1039.41
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 5.4.0-1041.43
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 5.4.0-1038.41
Upgrade
Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 5.4.0-1034.35
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 5.4.0-1039.42
Upgrade
Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 5.4.0-1030.33
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 5.4.0-1069.73+fips2
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 5.4.0-1073.76+fips1
Upgrade
Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 5.4.0-1067.71~20.04.1

Event History

Apr 17, 2025

CVE Published

via MITRE·06:01 PM

Data Sourced

via MITRE·06:01 PM

DescriptionSeverity

Data Sourced

via OSV·06:15 PM

DescriptionSeverityAffected Software

Data Sourced

via NVD·06:15 PM

RemedyDescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

What is the severity of CVE-2021-47668?

CVE-2021-47668 has been classified with a moderate severity level due to the potential for a use-after-free condition in the Linux kernel.

How do I fix CVE-2021-47668?

To fix CVE-2021-47668, you should update to the latest version of the Linux kernel that includes the patch addressing this vulnerability.

Which versions of the Linux kernel are affected by CVE-2021-47668?

CVE-2021-47668 affects multiple versions of the Linux kernel prior to the application of the relevant patches.

What is a use-after-free bug in the context of CVE-2021-47668?

In CVE-2021-47668, a use-after-free bug occurs when the memory of a data structure is accessed after it has been freed, potentially leading to memory corruption.

Can CVE-2021-47668 be exploited remotely?

Yes, an attacker with appropriate privileges could potentially exploit CVE-2021-47668, but remote exploitation is contingent on specific conditions being met.

CVE-2021-47668: can: dev: can_restart: fix use after free bug

Affected Software

Remediation

Event History

Frequently Asked Questions

What is the severity of CVE-2021-47668?

How do I fix CVE-2021-47668?

Which versions of the Linux kernel are affected by CVE-2021-47668?

What is a use-after-free bug in the context of CVE-2021-47668?

Can CVE-2021-47668 be exploited remotely?

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