CVE-2021-3178: Path Traversal

Published Jan 19, 2021
·
Updated

DISPUTED fs/nfsd/nfs3xdr.c in the Linux kernel through 5.10.8, when there is an NFS export of a subdirectory of a filesystem, allows remote attackers to traverse to other parts of the filesystem via READDIRPLUS. NOTE: some parties argue that such a subdirectory export is not intended to prevent this attack; see also the exports(5) nosubtreecheck default behavior.

Affected Software

85 affected componentsFixes available
Linux Linux kernel<=5.10.8
Fedoraproject Fedora=33
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
ubuntu/linux-aws<4.4.0-1087.91
4.4.0-1087.91
ubuntu/linux-azure<4.15.0-1109.121~14.04.1
4.15.0-1109.121~14.04.1
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<4.15.0-1095.102~16.04.1
4.15.0-1095.102~16.04.1
ubuntu/linux-azure<4.15.0-1109.121~16.04.1
4.15.0-1109.121~16.04.1
ubuntu/linux-gcp<4.15.0-1094.107~16.04.1
4.15.0-1094.107~16.04.1
ubuntu/linux-hwe<4.15.0-137.141~16.04.1
4.15.0-137.141~16.04.1
ubuntu/linux-kvm<4.4.0-1089.98
4.4.0-1089.98
ubuntu/linux-oracle<4.15.0-1066.74~16.04.1
4.15.0-1066.74~16.04.1
ubuntu/linux-raspi2<4.4.0-1147.157
4.4.0-1147.157
ubuntu/linux-snapdragon<4.4.0-1151.161
4.4.0-1151.161
ubuntu/linux-hwe-edge*
ubuntu/linux-fips<4.4.0-1057.63
4.4.0-1057.63
ubuntu/linux-fips*
ubuntu/linux<4.15.0-137.141
4.15.0-137.141
ubuntu/linux-aws<4.15.0-1095.102
4.15.0-1095.102
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<4.15.0-1109.121
4.15.0-1109.121
ubuntu/linux-azure-5.4<5.4.0-1041.43~18.04.1
5.4.0-1041.43~18.04.1
ubuntu/linux-dell300x<4.15.0-1013.17
4.15.0-1013.17
ubuntu/linux-gcp-4.15<4.15.0-1094.107
4.15.0-1094.107
ubuntu/linux-gcp-5.4<5.4.0-1038.41~18.04.1
5.4.0-1038.41~18.04.1
ubuntu/linux-gke-5.4<5.4.0-1037.39~18.04.1
5.4.0-1037.39~18.04.1
ubuntu/linux-gkeop-5.4<5.4.0-1011.12~18.04.2
5.4.0-1011.12~18.04.2
ubuntu/linux-hwe-5.4<5.4.0-67.75~18.04.1
5.4.0-67.75~18.04.1
ubuntu/linux-kvm<4.15.0-1086.88
4.15.0-1086.88
ubuntu/linux-oracle<4.15.0-1066.74
4.15.0-1066.74
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-raspi2<4.15.0-1080.85
4.15.0-1080.85
ubuntu/linux-snapdragon<4.15.0-1097.106
4.15.0-1097.106
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-gke-4.15*
ubuntu/linux-hwe*
ubuntu/linux-hwe-edge*
ubuntu/linux-oem*
ubuntu/linux-oracle-5.0*
ubuntu/linux-oracle-5.3*
ubuntu/linux-aws-fips<4.15.0-2038.40
4.15.0-2038.40
ubuntu/linux-azure-fips<4.15.0-2021.24
4.15.0-2021.24
ubuntu/linux-fips<4.15.0-1054.62
4.15.0-1054.62
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-gke<5.4.0-1037.39
5.4.0-1037.39
ubuntu/linux-gkeop<5.4.0-1011.12
5.4.0-1011.12
ubuntu/linux-hwe-5.8<5.8.0-49.55~20.04.1
5.8.0-49.55~20.04.1
ubuntu/linux-kvm<5.4.0-1034.35
5.4.0-1034.35
ubuntu/linux-oem-5.10<5.10.0-1014.15
5.10.0-1014.15
ubuntu/linux-oem-5.6<5.6.0-1053.57
5.6.0-1053.57
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-riscv-5.8<5.8.0-22.24~20.04.1
5.8.0-22.24~20.04.1
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-riscv*
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 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 to a version that resolves this vulnerability.

    Fixed in 4.4.0-1087.91
  3. Upgrade

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

    Fixed in 4.15.0-1109.121~14.04.1
  4. Upgrade

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

    Fixed in 4.4.0-204.236~14.04.1
  5. Upgrade

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

    Fixed in 4.4.0-204.236
  6. Upgrade

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

    Fixed in 4.4.0-1123.137
  7. Upgrade

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

    Fixed in 4.15.0-1095.102~16.04.1
  8. Upgrade

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

    Fixed in 4.15.0-1109.121~16.04.1
  9. Upgrade

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

    Fixed in 4.15.0-1094.107~16.04.1
  10. Upgrade

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

    Fixed in 4.15.0-137.141~16.04.1
  11. Upgrade

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

    Fixed in 4.4.0-1089.98
  12. Upgrade

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

    Fixed in 4.15.0-1066.74~16.04.1
  13. Upgrade

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

    Fixed in 4.4.0-1147.157
  14. Upgrade

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

    Fixed in 4.4.0-1151.161
  15. Upgrade

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

    Fixed in 4.4.0-1057.63
  16. Upgrade

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

    Fixed in 4.15.0-137.141
  17. Upgrade

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

    Fixed in 4.15.0-1095.102
  18. Upgrade

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

    Fixed in 5.4.0-1039.41~18.04.1
  19. Upgrade

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

    Fixed in 4.15.0-1109.121
  20. Upgrade

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

    Fixed in 5.4.0-1041.43~18.04.1
  21. Upgrade

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

    Fixed in 4.15.0-1013.17
  22. Upgrade

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

    Fixed in 4.15.0-1094.107
  23. Upgrade

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

    Fixed in 5.4.0-1038.41~18.04.1
  24. Upgrade

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

    Fixed in 5.4.0-1037.39~18.04.1
  25. Upgrade

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

    Fixed in 5.4.0-1011.12~18.04.2
  26. Upgrade

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

    Fixed in 5.4.0-67.75~18.04.1
  27. Upgrade

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

    Fixed in 4.15.0-1086.88
  28. Upgrade

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

    Fixed in 4.15.0-1066.74
  29. Upgrade

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

    Fixed in 5.4.0-1039.42~18.04.1
  30. Upgrade

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

    Fixed in 5.4.0-1030.33~18.04.1
  31. Upgrade

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

    Fixed in 4.15.0-1080.85
  32. Upgrade

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

    Fixed in 4.15.0-1097.106
  33. Upgrade

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

    Fixed in 4.15.0-2038.40
  34. Upgrade

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

    Fixed in 4.15.0-2021.24
  35. Upgrade

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

    Fixed in 4.15.0-1054.62
  36. Upgrade

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

    Fixed in 5.4.0-67.75
  37. Upgrade

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

    Fixed in 5.4.0-1039.41
  38. Upgrade

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

    Fixed in 5.4.0-1041.43
  39. Upgrade

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

    Fixed in 5.4.0-1038.41
  40. Upgrade

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

    Fixed in 5.4.0-1037.39
  41. Upgrade

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

    Fixed in 5.4.0-1011.12
  42. Upgrade

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

    Fixed in 5.8.0-49.55~20.04.1
  43. Upgrade

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

    Fixed in 5.4.0-1034.35
  44. Upgrade

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

    Fixed in 5.10.0-1014.15
  45. Upgrade

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

    Fixed in 5.6.0-1053.57
  46. Upgrade

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

    Fixed in 5.4.0-1039.42
  47. Upgrade

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

    Fixed in 5.4.0-1030.33
  48. Upgrade

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

    Fixed in 5.8.0-22.24~20.04.1
  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

Jan 19, 2021
CVE Published
via MITRE·06:44 AM
Data Sourced
via MITRE·06:44 AM
Description
Data Sourced
via OSV·07:15 AM
DescriptionSeverityAffected Software
Disputed
07:15 AM
Data Sourced
via NVD·07:15 AM
RemedyDescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2021-3178?

CVE-2021-3178 is considered a moderate severity vulnerability that can allow remote attackers to traverse the filesystem.

2

How do I fix CVE-2021-3178?

To remediate CVE-2021-3178, update the Linux kernel to version 5.10.223-1, 5.10.226-1 or later.

3

What software is affected by CVE-2021-3178?

CVE-2021-3178 affects the Linux kernel up to version 5.10.8 and specific distributions like Fedora 33 and Debian 9.0.

4

Can CVE-2021-3178 be exploited remotely?

Yes, CVE-2021-3178 can be exploited remotely via the READDIRPLUS functionality in NFS exports.

5

Is this vulnerability still a concern if I am using a patched version?

If you are using a patched version of the Linux kernel, the concerns related to CVE-2021-3178 should be mitigated.

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