CVE-2021-35477: Medium severity Linux Linux kernel vulnerability

Published Aug 2, 2021
·
Updated

In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because a certain preempting store operation does not necessarily occur before a store operation that has an attacker-controlled value.

Affected Software

97 affected componentsFixes available
Linux Linux kernel<=5.13.7
Debian Debian Linux=9.0
Fedoraproject Fedora=33
Fedoraproject Fedora=34
debian/linux
5.10.223-15.10.234-16.1.129-16.1.135-16.12.25-16.12.27-1
ubuntu/linux*
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<5.4.0-1059.62~18.04.1
5.4.0-1059.62~18.04.1
ubuntu/linux-azure-5.4<5.4.0-1063.66~18.04.1
5.4.0-1063.66~18.04.1
ubuntu/linux-gcp-5.4<5.4.0-1057.61~18.04.1
5.4.0-1057.61~18.04.1
ubuntu/linux-gke-5.4<5.4.0-1055.58~18.04.1
5.4.0-1055.58~18.04.1
ubuntu/linux-gkeop-5.4<5.4.0-1026.27~18.04.1
5.4.0-1026.27~18.04.1
ubuntu/linux-hwe-5.4<5.4.0-90.101~18.04.1
5.4.0-90.101~18.04.1
ubuntu/linux-oracle-5.4<5.4.0-1057.61~18.04.1
5.4.0-1057.61~18.04.1
ubuntu/linux-raspi-5.4<5.4.0-1046.50~18.04.1
5.4.0-1046.50~18.04.1
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<5.4.0-90.101
5.4.0-90.101
ubuntu/linux-aws<5.4.0-1059.62
5.4.0-1059.62
ubuntu/linux-aws-5.11<5.11.0-1019.20~20.04.1
5.11.0-1019.20~20.04.1
ubuntu/linux-azure<5.4.0-1063.66
5.4.0-1063.66
ubuntu/linux-azure-5.11<5.11.0-1017.18~20.04.1
5.11.0-1017.18~20.04.1
ubuntu/linux-bluefield<5.4.0-1021.24
5.4.0-1021.24
ubuntu/linux-gcp<5.4.0-1057.61
5.4.0-1057.61
ubuntu/linux-gcp-5.11<5.11.0-1020.22~20.04.1
5.11.0-1020.22~20.04.1
ubuntu/linux-gke<5.4.0-1055.58
5.4.0-1055.58
ubuntu/linux-gkeop<5.4.0-1026.27
5.4.0-1026.27
ubuntu/linux-hwe-5.11<5.11.0-37.41~20.04.2
5.11.0-37.41~20.04.2
ubuntu/linux-ibm<5.4.0-1007.8
5.4.0-1007.8
ubuntu/linux-kvm<5.4.0-1049.51
5.4.0-1049.51
ubuntu/linux-oem-5.10<5.10.0-1050.52
5.10.0-1050.52
ubuntu/linux-oem-5.13<5.13.0-1014.18
5.13.0-1014.18
ubuntu/linux-oracle<5.4.0-1057.61
5.4.0-1057.61
ubuntu/linux-oracle-5.11<5.11.0-1019.20~20.04.1
5.11.0-1019.20~20.04.1
ubuntu/linux-raspi<5.4.0-1046.50
5.4.0-1046.50
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-azure-fde-5.15<5.15.0-1114.123~20.04.1
5.15.0-1114.123~20.04.1
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<5.4.0-1036.42
5.4.0-1036.42
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 ubuntu/linux-aws-5.4 to a version that resolves this vulnerability.

    Fixed in 5.4.0-1059.62~18.04.1
  3. Upgrade

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

    Fixed in 5.4.0-1063.66~18.04.1
  4. Upgrade

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

    Fixed in 5.4.0-1057.61~18.04.1
  5. Upgrade

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

    Fixed in 5.4.0-1055.58~18.04.1
  6. Upgrade

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

    Fixed in 5.4.0-1026.27~18.04.1
  7. Upgrade

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

    Fixed in 5.4.0-90.101~18.04.1
  8. Upgrade

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

    Fixed in 5.4.0-1057.61~18.04.1
  9. Upgrade

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

    Fixed in 5.4.0-1046.50~18.04.1
  10. Upgrade

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

    Fixed in 5.4.0-90.101
  11. Upgrade

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

    Fixed in 5.4.0-1059.62
  12. Upgrade

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

    Fixed in 5.11.0-1019.20~20.04.1
  13. Upgrade

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

    Fixed in 5.4.0-1063.66
  14. Upgrade

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

    Fixed in 5.11.0-1017.18~20.04.1
  15. Upgrade

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

    Fixed in 5.4.0-1021.24
  16. Upgrade

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

    Fixed in 5.4.0-1057.61
  17. Upgrade

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

    Fixed in 5.11.0-1020.22~20.04.1
  18. Upgrade

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

    Fixed in 5.4.0-1055.58
  19. Upgrade

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

    Fixed in 5.4.0-1026.27
  20. Upgrade

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

    Fixed in 5.11.0-37.41~20.04.2
  21. Upgrade

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

    Fixed in 5.4.0-1007.8
  22. Upgrade

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

    Fixed in 5.4.0-1049.51
  23. Upgrade

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

    Fixed in 5.10.0-1050.52
  24. Upgrade

    Upgrade ubuntu/linux-oem-5.13 to a version that resolves this vulnerability.

    Fixed in 5.13.0-1014.18
  25. Upgrade

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

    Fixed in 5.4.0-1057.61
  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 5.4.0-1046.50
  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-azure-fde-5.15 to a version that resolves this vulnerability.

    Fixed in 5.15.0-1114.123~20.04.1
  30. Upgrade

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

    Fixed in 5.4.0-1069.73+fips2
  31. Upgrade

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

    Fixed in 5.4.0-1073.76+fips1
  32. Upgrade

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

    Fixed in 5.4.0-1036.42
  33. 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

Aug 2, 2021
CVE Published
via MITRE·03:57 AM
Data Sourced
via MITRE·03:57 AM
Description
Data Sourced
via OSV·04:15 AM
DescriptionSeverityAffected Software
Data Sourced
via NVD·04:15 AM
RemedyDescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2021-35477?

CVE-2021-35477 is classified as a medium severity vulnerability due to its potential to leak sensitive information from kernel memory.

2

How do I fix CVE-2021-35477?

To fix CVE-2021-35477, upgrade to a patched version of the Linux kernel beyond 5.13.7 or apply the relevant security patch if available.

3

Which versions of the Linux kernel are affected by CVE-2021-35477?

CVE-2021-35477 affects the Linux kernel versions through 5.13.7 inclusive.

4

Can CVE-2021-35477 be exploited remotely?

CVE-2021-35477 is primarily a local vulnerability and requires an unprivileged user to run a specially crafted BPF program to exploit it.

5

Is Debian Linux 9.0 vulnerable to CVE-2021-35477?

Yes, Debian Linux 9.0 is affected by CVE-2021-35477 and should be updated to a version with the relevant patches.

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