CVE-2020-25656: Use After Free

Published Oct 15, 2020
·
Updated

A flaw was found in Linux Kernel, where a race in KDGKBSENT and KDSKBSENT leads to use-after-free read in vtdokdgkbioctl

References: https://groups.google.com/g/syzkaller-bugs/c/kZsmxkpq3UI/m/J35PFexWBgAJ?pli=1

Other sources

A flaw was found in the Linux kernel. A use-after-free was found in the way the console subsystem was using ioctls KDGKBSENT and KDSKBSENT. A local user could use this flaw to get read memory access out of bounds. The highest threat from this vulnerability is to data confidentiality.

In vtdokdgkbioctl of keyboard.c, there is a possible use after free read due to a race condition. This could lead to local information disclosure with System execution privileges needed. User interaction is not needed for exploitation.

— OSV

Linux Kernel is vulnerable to a denial of service, caused by a use-after-free in the vtdokdgkbioctl function. By executing a specially-crafted program, a local authenticated attacker could exploit this vulnerability to cause the system to crash.

— IBM

Affected Software

98 affected componentsFixes available
redhat/kernel-rt<0:3.10.0-1160.21.1.rt56.1158.el7
0:3.10.0-1160.21.1.rt56.1158.el7
redhat/kernel<0:3.10.0-1160.21.1.el7
0:3.10.0-1160.21.1.el7
redhat/kernel<5.10
5.10
Linux Linux kernel<5.10
Linux Linux kernel=5.10-rc1
redhat Enterprise Linux=7.0
redhat Enterprise Linux=8.0
Debian Debian Linux=9.0
Starwindsoftware Starwind Virtual San Vsphere=v8-build12533
Starwindsoftware Starwind Virtual San Vsphere=v8-build12658
Starwindsoftware Starwind Virtual San Vsphere=v8-build12859
Starwindsoftware Starwind Virtual San Vsphere=v8-build13170
Starwindsoftware Starwind Virtual San Vsphere=v8-build13586
Starwindsoftware Starwind Virtual San Vsphere=v8-build13861
IBM Security Verify Governance<=ISVG 10.0.2
IBM Security Verify Governance, Identity Manager Software Stack<=ISVG 10.0.2
IBM Security Verify Governance, Identity Manager Virtual Appliance<=ISVG 10.0.2
IBM Security Verify Governance Identity Manager Container<=ISVG 10.0.2
debian/linux
5.10.223-15.10.234-16.1.129-16.1.135-16.12.25-1
android/:linux_kernel:>=:0<:2021-05-05
:2021-05-05
ubuntu/linux-aws<4.4.0-1083.87
4.4.0-1083.87
ubuntu/linux-azure<4.15.0-1103.114~14.04.1
4.15.0-1103.114~14.04.1
ubuntu/linux-lts-xenial<4.4.0-198.230~14.04.1
4.4.0-198.230~14.04.1
ubuntu/linux*
ubuntu/linux<4.4.0-198.230
4.4.0-198.230
ubuntu/linux-aws<4.4.0-1119.133
4.4.0-1119.133
ubuntu/linux-aws-hwe<4.15.0-1091.96~16.04.1
4.15.0-1091.96~16.04.1
ubuntu/linux-azure<4.15.0-1103.114~16.04.1
4.15.0-1103.114~16.04.1
ubuntu/linux-gcp<4.15.0-1091.104~16.04.1
4.15.0-1091.104~16.04.1
ubuntu/linux-hwe<4.15.0-129.132~16.04.1
4.15.0-129.132~16.04.1
ubuntu/linux-kvm<4.4.0-1085.94
4.4.0-1085.94
ubuntu/linux-oracle<4.15.0-1062.68~16.04.1
4.15.0-1062.68~16.04.1
ubuntu/linux-raspi2<4.4.0-1143.153
4.4.0-1143.153
ubuntu/linux-snapdragon<4.4.0-1147.157
4.4.0-1147.157
ubuntu/linux-hwe-edge*
ubuntu/linux-fips<4.4.0-1052.58
4.4.0-1052.58
ubuntu/linux-fips*
ubuntu/linux<4.15.0-129.132
4.15.0-129.132
ubuntu/linux-aws<4.15.0-1091.96
4.15.0-1091.96
ubuntu/linux-aws-5.4<5.4.0-1034.35~18.04.1
5.4.0-1034.35~18.04.1
ubuntu/linux-azure-4.15<4.15.0-1103.114
4.15.0-1103.114
ubuntu/linux-azure-5.4<5.4.0-1035.36~18.04.1
5.4.0-1035.36~18.04.1
ubuntu/linux-dell300x<4.15.0-1010.14
4.15.0-1010.14
ubuntu/linux-gcp-4.15<4.15.0-1091.104
4.15.0-1091.104
ubuntu/linux-gcp-5.4<5.4.0-1033.35~18.04.1
5.4.0-1033.35~18.04.1
ubuntu/linux-gke-4.15<4.15.0-1077.82
4.15.0-1077.82
ubuntu/linux-gke-5.4<5.4.0-1033.35~18.04.1
5.4.0-1033.35~18.04.1
ubuntu/linux-gkeop-5.4<5.4.0-1008.9~18.04.1
5.4.0-1008.9~18.04.1
ubuntu/linux-hwe-5.4<5.4.0-59.65~18.04.1
5.4.0-59.65~18.04.1
ubuntu/linux-kvm<4.15.0-1082.84
4.15.0-1082.84
ubuntu/linux-oracle<4.15.0-1062.68
4.15.0-1062.68
ubuntu/linux-oracle-5.4<5.4.0-1034.36~18.04.1
5.4.0-1034.36~18.04.1
ubuntu/linux-raspi-5.4<5.4.0-1026.29~18.04.1
5.4.0-1026.29~18.04.1
ubuntu/linux-raspi2<4.15.0-1077.82
4.15.0-1077.82
ubuntu/linux-snapdragon<4.15.0-1094.103
4.15.0-1094.103
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*
ubuntu/linux-hwe-edge*
ubuntu/linux-oem*
ubuntu/linux-oracle-5.0*
ubuntu/linux-oracle-5.3*
ubuntu/linux-aws-fips<4.15.0-2034.35
4.15.0-2034.35
ubuntu/linux-azure-fips<4.15.0-2016.18
4.15.0-2016.18
ubuntu/linux-fips<4.15.0-1049.56
4.15.0-1049.56
ubuntu/linux-aws-fips*
ubuntu/linux-azure-fips*
ubuntu/linux-fips*
ubuntu/linux-gcp-fips*
ubuntu/linux<5.4.0-59.65
5.4.0-59.65
ubuntu/linux-aws<5.4.0-1034.35
5.4.0-1034.35
ubuntu/linux-azure<5.4.0-1035.36
5.4.0-1035.36
ubuntu/linux-gcp<5.4.0-1033.35
5.4.0-1033.35
ubuntu/linux-hwe-5.8<5.8.0-44.50~20.04.1
5.8.0-44.50~20.04.1
ubuntu/linux-kvm<5.4.0-1031.32
5.4.0-1031.32
ubuntu/linux-oem-5.6<5.6.0-1050.54
5.6.0-1050.54
ubuntu/linux-oracle<5.4.0-1034.36
5.4.0-1034.36
ubuntu/linux-raspi<5.4.0-1026.29
5.4.0-1026.29
ubuntu/linux-riscv<5.4.0-40.45
5.4.0-40.45
ubuntu/linux-riscv-5.8<5.8.0-17.19~20.04.1
5.8.0-17.19~20.04.1
ubuntu/linux-azure-fde-5.15<5.15.0-1114.123~20.04.1
5.15.0-1114.123~20.04.1
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-raspi-realtime*
ubuntu/linux-vmware*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade redhat/kernel-rt to a version that resolves this vulnerability.

    Fixed in 0:3.10.0-1160.21.1.rt56.1158.el7
  2. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 0:3.10.0-1160.21.1.el7
  3. Upgrade

    Upgrade redhat/kernel to a version that resolves this vulnerability.

    Fixed in 5.10
  4. 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 6.12.25-1
  5. Upgrade

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

    Fixed in :2021-05-05
  6. Upgrade

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

    Fixed in 4.4.0-1083.87
  7. Upgrade

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

    Fixed in 4.15.0-1103.114~14.04.1
  8. Upgrade

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

    Fixed in 4.4.0-198.230~14.04.1
  9. Upgrade

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

    Fixed in 4.4.0-198.230
  10. Upgrade

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

    Fixed in 4.4.0-1119.133
  11. Upgrade

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

    Fixed in 4.15.0-1091.96~16.04.1
  12. Upgrade

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

    Fixed in 4.15.0-1103.114~16.04.1
  13. Upgrade

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

    Fixed in 4.15.0-1091.104~16.04.1
  14. Upgrade

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

    Fixed in 4.15.0-129.132~16.04.1
  15. Upgrade

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

    Fixed in 4.4.0-1085.94
  16. Upgrade

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

    Fixed in 4.15.0-1062.68~16.04.1
  17. Upgrade

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

    Fixed in 4.4.0-1143.153
  18. Upgrade

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

    Fixed in 4.4.0-1147.157
  19. Upgrade

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

    Fixed in 4.4.0-1052.58
  20. Upgrade

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

    Fixed in 4.15.0-129.132
  21. Upgrade

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

    Fixed in 4.15.0-1091.96
  22. Upgrade

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

    Fixed in 5.4.0-1034.35~18.04.1
  23. Upgrade

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

    Fixed in 4.15.0-1103.114
  24. Upgrade

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

    Fixed in 5.4.0-1035.36~18.04.1
  25. Upgrade

    Upgrade ubuntu/linux-dell300x to a version that resolves this vulnerability.

    Fixed in 4.15.0-1010.14
  26. Upgrade

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

    Fixed in 4.15.0-1091.104
  27. Upgrade

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

    Fixed in 5.4.0-1033.35~18.04.1
  28. Upgrade

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

    Fixed in 4.15.0-1077.82
  29. Upgrade

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

    Fixed in 5.4.0-1033.35~18.04.1
  30. Upgrade

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

    Fixed in 5.4.0-1008.9~18.04.1
  31. Upgrade

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

    Fixed in 5.4.0-59.65~18.04.1
  32. Upgrade

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

    Fixed in 4.15.0-1082.84
  33. Upgrade

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

    Fixed in 4.15.0-1062.68
  34. Upgrade

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

    Fixed in 5.4.0-1034.36~18.04.1
  35. Upgrade

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

    Fixed in 5.4.0-1026.29~18.04.1
  36. Upgrade

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

    Fixed in 4.15.0-1077.82
  37. Upgrade

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

    Fixed in 4.15.0-1094.103
  38. Upgrade

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

    Fixed in 4.15.0-2034.35
  39. Upgrade

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

    Fixed in 4.15.0-2016.18
  40. Upgrade

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

    Fixed in 4.15.0-1049.56
  41. Upgrade

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

    Fixed in 5.4.0-59.65
  42. Upgrade

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

    Fixed in 5.4.0-1034.35
  43. Upgrade

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

    Fixed in 5.4.0-1035.36
  44. Upgrade

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

    Fixed in 5.4.0-1033.35
  45. Upgrade

    Upgrade ubuntu/linux-hwe-5.8 to a version that resolves this vulnerability.

    Fixed in 5.8.0-44.50~20.04.1
  46. Upgrade

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

    Fixed in 5.4.0-1031.32
  47. Upgrade

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

    Fixed in 5.6.0-1050.54
  48. Upgrade

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

    Fixed in 5.4.0-1034.36
  49. Upgrade

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

    Fixed in 5.4.0-1026.29
  50. Upgrade

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

    Fixed in 5.4.0-40.45
  51. Upgrade

    Upgrade ubuntu/linux-riscv-5.8 to a version that resolves this vulnerability.

    Fixed in 5.8.0-17.19~20.04.1
  52. 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
  53. Upgrade

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

    Fixed in 5.4.0-1069.73+fips2
  54. Upgrade

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

    Fixed in 5.4.0-1073.76+fips1
  55. 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

Oct 16, 2020
CVE Published
12:00 AM
Dec 2, 2020
CVE Published
via MITRE·12:00 AM
Data Sourced
via MITRE·12:00 AM
DescriptionWeakness
Data Sourced
via OSV·01:15 AM
DescriptionSeverityAffected Software
May 1, 2021
Advisory Published
via OSV·12:00 AM

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

1

What is the severity of CVE-2020-25656?

CVE-2020-25656 has a medium severity rating due to the potential for a use-after-free vulnerability in the Linux Kernel.

2

How do I fix CVE-2020-25656?

To fix CVE-2020-25656, update your Linux Kernel to the recommended versions, such as 5.10 or apply specific patches provided by your distribution.

3

Which systems are affected by CVE-2020-25656?

CVE-2020-25656 affects various versions of the Linux Kernel, particularly those in Red Hat Enterprise Linux 7, 8, and Debian 9.0, among others.

4

What is the exploitability of CVE-2020-25656?

CVE-2020-25656 is considered exploitable under specific conditions where a race condition may lead to unauthorized memory access.

5

Are there any known mitigations for CVE-2020-25656?

Currently, the primary mitigation for CVE-2020-25656 is to ensure that relevant software is updated to patched versions that address the vulnerability.

Company

Resources

Contact

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