CVE-2020-12656: Medium severity Linux Linux kernel vulnerability

Published May 5, 2020
·
Updated

DISPUTED gssmechfree in net/sunrpc/authgss/gssmechswitch.c in the rpcsecgsskrb5 implementation in the Linux kernel through 5.6.10 lacks certain domainrelease calls, leading to a memory leak. Note: This was disputed with the assertion that the issue does not grant any access not already available. It is a problem that on unloading a specific kernel module some memory is leaked, but loading kernel modules is a privileged operation. A user could also write a kernel module to consume any amount of memory they like and load that replicating the effect of this bug.

Affected Software

86 affected componentsFixes available
Linux Linux kernel<=5.6.10
Canonical Ubuntu Linux=14.04
Canonical Ubuntu Linux=16.04
Canonical Ubuntu Linux=18.04
Canonical Ubuntu Linux=20.04
openSUSE Leap=15.1
openSUSE Leap=15.2
debian/linux
6.1.176-16.1.190-16.12.107-16.12.113-17.2.12-17.2.13-1
ubuntu/linux-aws<4.4.0-1075.79
4.4.0-1075.79
ubuntu/linux-azure<4.15.0-1093.103~14.04.1
4.15.0-1093.103~14.04.1
ubuntu/linux-lts-xenial<4.4.0-186.216~14.04.1
4.4.0-186.216~14.04.1
ubuntu/linux*
ubuntu/linux<4.4.0-186.216
4.4.0-186.216
ubuntu/linux-aws<4.4.0-1111.123
4.4.0-1111.123
ubuntu/linux-aws-hwe<4.15.0-1080.84~16.04.1
4.15.0-1080.84~16.04.1
ubuntu/linux-azure<4.15.0-1093.103~16.04.1
4.15.0-1093.103~16.04.1
ubuntu/linux-gcp<4.15.0-1081.92~16.04.1
4.15.0-1081.92~16.04.1
ubuntu/linux-hwe<4.15.0-115.116~16.04.1
4.15.0-115.116~16.04.1
ubuntu/linux-kvm<4.4.0-1077.84
4.4.0-1077.84
ubuntu/linux-oracle<4.15.0-1051.55~16.04.1
4.15.0-1051.55~16.04.1
ubuntu/linux-raspi2<4.4.0-1136.145
4.4.0-1136.145
ubuntu/linux-snapdragon<4.4.0-1140.148
4.4.0-1140.148
ubuntu/linux-hwe-edge*
ubuntu/linux-fips<4.4.0-1043.48
4.4.0-1043.48
ubuntu/linux-fips*
ubuntu/linux<4.15.0-115.116
4.15.0-115.116
ubuntu/linux-aws<4.15.0-1080.84
4.15.0-1080.84
ubuntu/linux-aws-5.4<5.4.0-1022.22~18.04.1
5.4.0-1022.22~18.04.1
ubuntu/linux-azure-4.15<4.15.0-1093.103
4.15.0-1093.103
ubuntu/linux-azure-5.4<5.4.0-1023.23~18.04.1
5.4.0-1023.23~18.04.1
ubuntu/linux-gcp-4.15<4.15.0-1081.92
4.15.0-1081.92
ubuntu/linux-gcp-5.4<5.4.0-1022.22~18.04.1
5.4.0-1022.22~18.04.1
ubuntu/linux-gke-4.15<4.15.0-1067.70
4.15.0-1067.70
ubuntu/linux-gke-5.0<5.0.0-1045.46
5.0.0-1045.46
ubuntu/linux-gke-5.3<5.3.0-1032.34~18.04.1
5.3.0-1032.34~18.04.1
ubuntu/linux-hwe<5.3.0-64.58~18.04.1
5.3.0-64.58~18.04.1
ubuntu/linux-hwe-5.4<5.4.0-45.49~18.04.2
5.4.0-45.49~18.04.2
ubuntu/linux-kvm<4.15.0-1072.73
4.15.0-1072.73
ubuntu/linux-oem<4.15.0-1094.104
4.15.0-1094.104
ubuntu/linux-oem-osp1<5.0.0-1065.70
5.0.0-1065.70
ubuntu/linux-oracle<4.15.0-1051.55
4.15.0-1051.55
ubuntu/linux-oracle-5.4<5.4.0-1022.22~18.04.1
5.4.0-1022.22~18.04.1
ubuntu/linux-raspi-5.4<5.4.0-1016.17~18.04.1
5.4.0-1016.17~18.04.1
ubuntu/linux-raspi2<4.15.0-1068.72
4.15.0-1068.72
ubuntu/linux-raspi2-5.3<5.3.0-1030.32~18.04.2
5.3.0-1030.32~18.04.2
ubuntu/linux-snapdragon<4.15.0-1084.92
4.15.0-1084.92
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-gcp-edge*
ubuntu/linux-hwe-edge*
ubuntu/linux-oracle-5.0*
ubuntu/linux-oracle-5.3*
ubuntu/linux-aws-fips<4.15.0-2025.25
4.15.0-2025.25
ubuntu/linux-azure-fips<4.15.0-2007.8
4.15.0-2007.8
ubuntu/linux-fips<4.15.0-1039.44
4.15.0-1039.44
ubuntu/linux-aws-fips*
ubuntu/linux-azure-fips*
ubuntu/linux-gcp-fips*
ubuntu/linux<5.4.0-45.49
5.4.0-45.49
ubuntu/linux-aws<5.4.0-1022.22
5.4.0-1022.22
ubuntu/linux-azure<5.4.0-1023.23
5.4.0-1023.23
ubuntu/linux-gcp<5.4.0-1022.22
5.4.0-1022.22
ubuntu/linux-kvm<5.4.0-1021.21
5.4.0-1021.21
ubuntu/linux-oem-5.6<5.6.0-1031.32
5.6.0-1031.32
ubuntu/linux-oracle<5.4.0-1022.22
5.4.0-1022.22
ubuntu/linux-raspi<5.4.0-1016.17
5.4.0-1016.17
ubuntu/linux-riscv<5.4.0-31.35
5.4.0-31.35
ubuntu/linux-azure-fde*
ubuntu/linux-azure-fde-5.15<5.15.0-1114.123~20.04.1
5.15.0-1114.123~20.04.1
ubuntu/linux-gke*
ubuntu/linux-raspi2*
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-intel-iot-realtime*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-raspi-realtime*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

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

    Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.107-1Fixed in 6.12.113-1Fixed in 7.2.12-1Fixed in 7.2.13-1
  2. Upgrade

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

    Fixed in 4.4.0-1075.79
  3. Upgrade

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

    Fixed in 4.15.0-1093.103~14.04.1
  4. Upgrade

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

    Fixed in 4.4.0-186.216~14.04.1
  5. Upgrade

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

    Fixed in 4.4.0-186.216
  6. Upgrade

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

    Fixed in 4.4.0-1111.123
  7. Upgrade

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

    Fixed in 4.15.0-1080.84~16.04.1
  8. Upgrade

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

    Fixed in 4.15.0-1093.103~16.04.1
  9. Upgrade

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

    Fixed in 4.15.0-1081.92~16.04.1
  10. Upgrade

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

    Fixed in 4.15.0-115.116~16.04.1
  11. Upgrade

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

    Fixed in 4.4.0-1077.84
  12. Upgrade

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

    Fixed in 4.15.0-1051.55~16.04.1
  13. Upgrade

    Upgrade ubuntu/linux-raspi2 to a version that resolves this vulnerability.

    Fixed in 4.4.0-1136.145
  14. Upgrade

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

    Fixed in 4.4.0-1140.148
  15. Upgrade

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

    Fixed in 4.4.0-1043.48
  16. Upgrade

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

    Fixed in 4.15.0-115.116
  17. Upgrade

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

    Fixed in 4.15.0-1080.84
  18. Upgrade

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

    Fixed in 5.4.0-1022.22~18.04.1
  19. Upgrade

    Upgrade ubuntu/linux-azure-4.15 to a version that resolves this vulnerability.

    Fixed in 4.15.0-1093.103
  20. Upgrade

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

    Fixed in 5.4.0-1023.23~18.04.1
  21. Upgrade

    Upgrade ubuntu/linux-gcp-4.15 to a version that resolves this vulnerability.

    Fixed in 4.15.0-1081.92
  22. Upgrade

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

    Fixed in 5.4.0-1022.22~18.04.1
  23. Upgrade

    Upgrade ubuntu/linux-gke-4.15 to a version that resolves this vulnerability.

    Fixed in 4.15.0-1067.70
  24. Upgrade

    Upgrade ubuntu/linux-gke-5.0 to a version that resolves this vulnerability.

    Fixed in 5.0.0-1045.46
  25. Upgrade

    Upgrade ubuntu/linux-gke-5.3 to a version that resolves this vulnerability.

    Fixed in 5.3.0-1032.34~18.04.1
  26. Upgrade

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

    Fixed in 5.3.0-64.58~18.04.1
  27. Upgrade

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

    Fixed in 5.4.0-45.49~18.04.2
  28. Upgrade

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

    Fixed in 4.15.0-1072.73
  29. Upgrade

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

    Fixed in 4.15.0-1094.104
  30. Upgrade

    Upgrade ubuntu/linux-oem-osp1 to a version that resolves this vulnerability.

    Fixed in 5.0.0-1065.70
  31. Upgrade

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

    Fixed in 4.15.0-1051.55
  32. Upgrade

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

    Fixed in 5.4.0-1022.22~18.04.1
  33. Upgrade

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

    Fixed in 5.4.0-1016.17~18.04.1
  34. Upgrade

    Upgrade ubuntu/linux-raspi2 to a version that resolves this vulnerability.

    Fixed in 4.15.0-1068.72
  35. Upgrade

    Upgrade ubuntu/linux-raspi2-5.3 to a version that resolves this vulnerability.

    Fixed in 5.3.0-1030.32~18.04.2
  36. Upgrade

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

    Fixed in 4.15.0-1084.92
  37. Upgrade

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

    Fixed in 4.15.0-2025.25
  38. Upgrade

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

    Fixed in 4.15.0-2007.8
  39. Upgrade

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

    Fixed in 4.15.0-1039.44
  40. Upgrade

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

    Fixed in 5.4.0-45.49
  41. Upgrade

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

    Fixed in 5.4.0-1022.22
  42. Upgrade

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

    Fixed in 5.4.0-1023.23
  43. Upgrade

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

    Fixed in 5.4.0-1022.22
  44. Upgrade

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

    Fixed in 5.4.0-1021.21
  45. Upgrade

    Upgrade ubuntu/linux-oem-5.6 to a version that resolves this vulnerability.

    Fixed in 5.6.0-1031.32
  46. Upgrade

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

    Fixed in 5.4.0-1022.22
  47. Upgrade

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

    Fixed in 5.4.0-1016.17
  48. Upgrade

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

    Fixed in 5.4.0-31.35
  49. 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
  50. Upgrade

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

    Fixed in 5.4.0-1069.73+fips2
  51. Upgrade

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

    Fixed in 5.4.0-1073.76+fips1
  52. 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

May 5, 2020
CVE Published
via Ubuntu·12:00 AM
Data Sourced
via Ubuntu·12:00 AM
RemedyDescriptionSeverityAffected Software
CVE Published
via MITRE·05:42 AM
Data Sourced
via MITRE·05:42 AM
Description
Data Sourced
via OSV·06:15 AM
DescriptionSeverityAffected Software
Disputed
06:15 AM
Data Sourced
via NVD·06:15 AM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2020-12656?

CVE-2020-12656 is considered a medium severity vulnerability due to the potential for memory leaks.

2

What systems are affected by CVE-2020-12656?

CVE-2020-12656 affects Linux Kernel versions up to 5.6.10 and specific versions of Ubuntu and openSUSE.

3

How do I fix CVE-2020-12656?

To fix CVE-2020-12656, upgrade to a patched version of the Linux Kernel or the relevant operating system package.

4

Is there any exploit for CVE-2020-12656?

CVE-2020-12656 does not grant new access but may lead to resource exhaustion due to a memory leak.

5

What is the impact of CVE-2020-12656?

The impact of CVE-2020-12656 includes potential denial of service caused by memory leaks affecting system stability.

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