CVE-2021-33624: Medium severity Linux Linux kernel vulnerability

Published Jun 23, 2021
·
Updated

In kernel/bpf/verifier.c in the Linux kernel before 5.12.13, a branch can be mispredicted (e.g., because of type confusion) and consequently an unprivileged BPF program can read arbitrary memory locations via a side-channel attack, aka CID-9183671af6db.

Affected Software

93 affected componentsFixes available
Linux Linux kernel<5.12.13
Debian Debian Linux=9.0
debian/linux
5.10.223-15.10.234-16.1.129-16.1.135-16.12.25-16.12.27-1
android/:linux_kernel:>=:0<:2022-03-05
:2022-03-05
ubuntu/linux-aws*
ubuntu/linux-azure*
ubuntu/linux-lts-xenial*
ubuntu/linux*
ubuntu/linux-aws*
ubuntu/linux-aws-hwe*
ubuntu/linux-azure*
ubuntu/linux-gcp*
ubuntu/linux-hwe*
ubuntu/linux-hwe-edge*
ubuntu/linux-kvm*
ubuntu/linux-oracle*
ubuntu/linux-fips*
ubuntu/linux-fips*
ubuntu/linux-aws-5.4<5.4.0-1057.60~18.04.1
5.4.0-1057.60~18.04.1
ubuntu/linux-azure-5.4<5.4.0-1059.62~18.04.1
5.4.0-1059.62~18.04.1
ubuntu/linux-gcp-5.4<5.4.0-1053.57~18.04.1
5.4.0-1053.57~18.04.1
ubuntu/linux-gke-5.4<5.4.0-1053.56~18.04.1
5.4.0-1053.56~18.04.1
ubuntu/linux-gkeop-5.4<5.4.0-1024.25~18.04.1
5.4.0-1024.25~18.04.1
ubuntu/linux-hwe-5.4<5.4.0-87.98~18.04.1
5.4.0-87.98~18.04.1
ubuntu/linux-oracle-5.4<5.4.0-1055.59~18.04.1
5.4.0-1055.59~18.04.1
ubuntu/linux-raspi-5.4<5.4.0-1044.48~18.04.1
5.4.0-1044.48~18.04.1
ubuntu/linux*
ubuntu/linux-aws*
ubuntu/linux-aws-5.0*
ubuntu/linux-aws-5.3*
ubuntu/linux-azure*
ubuntu/linux-azure-4.15*
ubuntu/linux-azure-5.3*
ubuntu/linux-azure-edge*
ubuntu/linux-gcp*
ubuntu/linux-gcp-4.15*
ubuntu/linux-gcp-5.3*
ubuntu/linux-gcp-edge*
ubuntu/linux-gke-4.15*
ubuntu/linux-hwe*
ubuntu/linux-hwe-edge*
ubuntu/linux-kvm*
ubuntu/linux-oem*
ubuntu/linux-oracle*
ubuntu/linux-oracle-5.0*
ubuntu/linux-oracle-5.3*
ubuntu/linux-aws-fips*
ubuntu/linux-azure-fips*
ubuntu/linux-fips*
ubuntu/linux-gcp-fips*
ubuntu/linux-aws-fips*
ubuntu/linux-azure-fips*
ubuntu/linux-fips*
ubuntu/linux-gcp-fips*
ubuntu/linux<5.4.0-88.99
5.4.0-88.99
ubuntu/linux-aws<5.4.0-1057.60
5.4.0-1057.60
ubuntu/linux-aws-5.11<5.11.0-1019.20~20.04.1
5.11.0-1019.20~20.04.1
ubuntu/linux-azure<5.4.0-1059.62
5.4.0-1059.62
ubuntu/linux-azure-5.11<5.11.0-1017.18~20.04.1
5.11.0-1017.18~20.04.1
ubuntu/linux-bluefield<5.4.0-1019.22
5.4.0-1019.22
ubuntu/linux-gcp<5.4.0-1053.57
5.4.0-1053.57
ubuntu/linux-gcp-5.11<5.11.0-1020.22~20.04.1
5.11.0-1020.22~20.04.1
ubuntu/linux-gke<5.4.0-1053.56
5.4.0-1053.56
ubuntu/linux-gkeop<5.4.0-1024.25
5.4.0-1024.25
ubuntu/linux-hwe-5.11<5.11.0-37.41~20.04.2
5.11.0-37.41~20.04.2
ubuntu/linux-ibm<5.4.0-1005.6
5.4.0-1005.6
ubuntu/linux-kvm<5.4.0-1047.49
5.4.0-1047.49
ubuntu/linux-oem-5.10<5.10.0-1050.52
5.10.0-1050.52
ubuntu/linux-oracle<5.4.0-1055.59
5.4.0-1055.59
ubuntu/linux-oracle-5.11<5.11.0-1019.20~20.04.1
5.11.0-1019.20~20.04.1
ubuntu/linux-raspi<5.4.0-1044.48
5.4.0-1044.48
ubuntu/linux-riscv-5.11<5.11.0-1020.21~20.04.1
5.11.0-1020.21~20.04.1
ubuntu/linux-aws-5.8*
ubuntu/linux-azure-5.8*
ubuntu/linux-gcp-5.8*
ubuntu/linux-hwe-5.8*
ubuntu/linux-oem-5.6*
ubuntu/linux-oracle-5.8*
ubuntu/linux-raspi2*
ubuntu/linux-riscv*
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-fips<5.4.0-1034.40
5.4.0-1034.40
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-fips*
ubuntu/linux-gcp-fips*
ubuntu/linux-intel-iot-realtime*
ubuntu/linux-realtime*
ubuntu/linux-raspi-realtime*
ubuntu/linux-vmware*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. 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
  2. Upgrade

    Upgrade android/:linux_kernel: to a version that resolves this vulnerability.

    Fixed in :2022-03-05
  3. Upgrade

    Upgrade ubuntu/linux-aws-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1057.60~18.04.1
  4. Upgrade

    Upgrade ubuntu/linux-azure-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1059.62~18.04.1
  5. Upgrade

    Upgrade ubuntu/linux-gcp-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1053.57~18.04.1
  6. Upgrade

    Upgrade ubuntu/linux-gke-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1053.56~18.04.1
  7. Upgrade

    Upgrade ubuntu/linux-gkeop-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1024.25~18.04.1
  8. Upgrade

    Upgrade ubuntu/linux-hwe-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-87.98~18.04.1
  9. Upgrade

    Upgrade ubuntu/linux-oracle-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1055.59~18.04.1
  10. Upgrade

    Upgrade ubuntu/linux-raspi-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1044.48~18.04.1
  11. Upgrade

    Upgrade ubuntu/linux to a version that resolves this vulnerability.

    Fixed in 5.4.0-88.99
  12. Upgrade

    Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.

    Fixed in 5.4.0-1057.60
  13. Upgrade

    Upgrade ubuntu/linux-aws-5.11 to a version that resolves this vulnerability.

    Fixed in 5.11.0-1019.20~20.04.1
  14. Upgrade

    Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.

    Fixed in 5.4.0-1059.62
  15. Upgrade

    Upgrade ubuntu/linux-azure-5.11 to a version that resolves this vulnerability.

    Fixed in 5.11.0-1017.18~20.04.1
  16. Upgrade

    Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.

    Fixed in 5.4.0-1019.22
  17. Upgrade

    Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.

    Fixed in 5.4.0-1053.57
  18. Upgrade

    Upgrade ubuntu/linux-gcp-5.11 to a version that resolves this vulnerability.

    Fixed in 5.11.0-1020.22~20.04.1
  19. Upgrade

    Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.

    Fixed in 5.4.0-1053.56
  20. Upgrade

    Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.

    Fixed in 5.4.0-1024.25
  21. Upgrade

    Upgrade ubuntu/linux-hwe-5.11 to a version that resolves this vulnerability.

    Fixed in 5.11.0-37.41~20.04.2
  22. Upgrade

    Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.

    Fixed in 5.4.0-1005.6
  23. Upgrade

    Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.

    Fixed in 5.4.0-1047.49
  24. Upgrade

    Upgrade ubuntu/linux-oem-5.10 to a version that resolves this vulnerability.

    Fixed in 5.10.0-1050.52
  25. Upgrade

    Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.

    Fixed in 5.4.0-1055.59
  26. Upgrade

    Upgrade ubuntu/linux-oracle-5.11 to a version that resolves this vulnerability.

    Fixed in 5.11.0-1019.20~20.04.1
  27. Upgrade

    Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.

    Fixed in 5.4.0-1044.48
  28. Upgrade

    Upgrade ubuntu/linux-riscv-5.11 to a version that resolves this vulnerability.

    Fixed in 5.11.0-1020.21~20.04.1
  29. Upgrade

    Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.

    Fixed in 5.4.0-1069.73+fips2
  30. Upgrade

    Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.

    Fixed in 5.4.0-1073.76+fips1
  31. Upgrade

    Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.

    Fixed in 5.4.0-1034.40
  32. Upgrade

    Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.

    Fixed in 5.4.0-1067.71~20.04.1
  33. Upgrade

    Upgrade Linux kernel to a version that resolves this vulnerability.

    Fixed in 5.12.13

Event History

Jun 23, 2021
CVE Published
via MITRE·03:37 PM
Data Sourced
via MITRE·03:37 PM
Description
Data Sourced
via OSV·04:15 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·04:15 PM
RemedyDescriptionSeverityWeaknessAffected Software
Jun 25, 2021
Exploit Published
via GitHub·10:19 PM
Mar 1, 2022
Advisory Published
via OSV·12:00 AM

Frequently Asked Questions

1

What is the severity of CVE-2021-33624?

CVE-2021-33624 is classified as a medium severity vulnerability due to its potential to allow unprivileged BPF programs to read arbitrary memory locations.

2

How do I fix CVE-2021-33624?

To resolve CVE-2021-33624, update your Linux kernel to version 5.12.13 or later.

3

What type of attack does CVE-2021-33624 involve?

CVE-2021-33624 involves a side-channel attack enabled by branch misprediction due to type confusion in the BPF verifier.

4

Which versions of the Linux kernel are affected by CVE-2021-33624?

CVE-2021-33624 affects Linux kernel versions prior to 5.12.13.

5

Are there specific distributions impacted by CVE-2021-33624?

Yes, Debian and its variants are among the affected distributions for CVE-2021-33624.

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