CVE-2021-47245: netfilter: synproxy: Fix out of bounds when parsing TCP options

Published May 21, 2024
·
Updated

In the Linux kernel, the following vulnerability has been resolved:

netfilter: synproxy: Fix out of bounds when parsing TCP options

The TCP option parser in synproxy (synproxyparseoptions) could read one byte out of bounds. When the length is 1, the execution flow gets into the loop, reads one byte of the opcode, and if the opcode is neither TCPOPTEOL nor TCPOPTNOP, it reads one more byte, which exceeds the length of 1.

This fix is inspired by commit 9609dad263f8 ("ipv4: tcpinput: fix stack out of bounds when parsing TCP options.").

v2 changes:

Added an early return when length < 0 to avoid calling skbheaderpointer with negative length.

Affected Software

131 affected componentsFixes available
Linux Linux kernel>=3.12<4.4.274
Linux Linux kernel>=4.5<4.9.274
Linux Linux kernel>=4.10<4.14.238
Linux Linux kernel>=4.15<4.19.196
Linux Linux kernel>=4.20<5.4.128
Linux Linux kernel>=5.5<5.10.46
Linux Linux kernel>=5.11<5.12.13
Linux Linux kernel=5.13-rc1
Linux Linux kernel=5.13-rc2
Linux Linux kernel=5.13-rc3
Linux Linux kernel=5.13-rc4
Linux Linux kernel=5.13-rc5
Linux Linux kernel=5.13-rc6
ubuntu/linux-azure<4.15.0-1123.136~14.04.1
4.15.0-1123.136~14.04.1
ubuntu/linux*
ubuntu/linux-aws<4.4.0-1143.149
4.4.0-1143.149
ubuntu/linux-lts-xenial<4.4.0-268.302~14.04.1
4.4.0-268.302~14.04.1
ubuntu/linux<4.4.0-268.302
4.4.0-268.302
ubuntu/linux-aws<4.4.0-1181.196
4.4.0-1181.196
ubuntu/linux-aws-hwe<4.15.0-1111.118~16.04.1
4.15.0-1111.118~16.04.1
ubuntu/linux-azure<4.15.0-1123.136~16.04.1
4.15.0-1123.136~16.04.1
ubuntu/linux-gcp<4.15.0-1108.122~16.04.1
4.15.0-1108.122~16.04.1
ubuntu/linux-hwe<4.15.0-156.163~16.04.1
4.15.0-156.163~16.04.1
ubuntu/linux-kvm<4.4.0-1144.155
4.4.0-1144.155
ubuntu/linux-oracle<4.15.0-1080.88~16.04.1
4.15.0-1080.88~16.04.1
ubuntu/linux-hwe-edge*
ubuntu/linux-fips<4.4.0-1113.120
4.4.0-1113.120
ubuntu/linux-fips*
ubuntu/linux<4.15.0-156.163
4.15.0-156.163
ubuntu/linux-aws<4.15.0-1111.118
4.15.0-1111.118
ubuntu/linux-aws-5.4<5.4.0-1055.58~18.04.1
5.4.0-1055.58~18.04.1
ubuntu/linux-azure-4.15<4.15.0-1123.136
4.15.0-1123.136
ubuntu/linux-azure-5.4<5.4.0-1056.58~18.04.1
5.4.0-1056.58~18.04.1
ubuntu/linux-gcp-4.15<4.15.0-1108.122
4.15.0-1108.122
ubuntu/linux-gcp-5.4<5.4.0-1051.55~18.04.1
5.4.0-1051.55~18.04.1
ubuntu/linux-hwe-5.4<5.4.0-81.91~18.04.1
5.4.0-81.91~18.04.1
ubuntu/linux-kvm<4.15.0-1099.101
4.15.0-1099.101
ubuntu/linux-oracle<4.15.0-1080.88
4.15.0-1080.88
ubuntu/linux-oracle-5.4<5.4.0-1053.57~18.04.1
5.4.0-1053.57~18.04.1
ubuntu/linux-raspi-5.4<5.4.0-1042.46~18.04.3
5.4.0-1042.46~18.04.3
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-gke-4.15*
ubuntu/linux-gke-5.4*
ubuntu/linux-gkeop-5.4*
ubuntu/linux-hwe*
ubuntu/linux-hwe-edge*
ubuntu/linux-oem*
ubuntu/linux-oracle-5.0*
ubuntu/linux-oracle-5.3*
ubuntu/linux-aws-fips<4.15.0-2053.55
4.15.0-2053.55
ubuntu/linux-azure-fips<4.15.0-2035.39
4.15.0-2035.39
ubuntu/linux-fips<4.15.0-1069.78
4.15.0-1069.78
ubuntu/linux-gcp-fips<4.15.0-2018.20
4.15.0-2018.20
ubuntu/linux-aws-fips*
ubuntu/linux-azure-fips*
ubuntu/linux-fips*
ubuntu/linux-gcp-fips*
ubuntu/linux<5.4.0-81.91
5.4.0-81.91
ubuntu/linux-aws<5.4.0-1055.58
5.4.0-1055.58
ubuntu/linux-azure<5.4.0-1056.58
5.4.0-1056.58
ubuntu/linux-bluefield<5.4.0-1019.22
5.4.0-1019.22
ubuntu/linux-gcp<5.4.0-1051.55
5.4.0-1051.55
ubuntu/linux-gkeop<5.4.0-1022.23
5.4.0-1022.23
ubuntu/linux-kvm<5.4.0-1045.47
5.4.0-1045.47
ubuntu/linux-oracle<5.4.0-1053.57
5.4.0-1053.57
ubuntu/linux-raspi<5.4.0-1042.46
5.4.0-1042.46
ubuntu/linux-aws-5.11*
ubuntu/linux-aws-5.13*
ubuntu/linux-aws-5.8*
ubuntu/linux-azure-5.11*
ubuntu/linux-azure-5.13*
ubuntu/linux-azure-5.8*
ubuntu/linux-azure-fde*
ubuntu/linux-gcp-5.11*
ubuntu/linux-gcp-5.13*
ubuntu/linux-gcp-5.8*
ubuntu/linux-gke*
ubuntu/linux-gke-5.15*
ubuntu/linux-hwe-5.11*
ubuntu/linux-hwe-5.13*
ubuntu/linux-hwe-5.8*
ubuntu/linux-intel-5.13*
ubuntu/linux-oem-5.10*
ubuntu/linux-oem-5.13*
ubuntu/linux-oem-5.6*
ubuntu/linux-oracle-5.11*
ubuntu/linux-oracle-5.13*
ubuntu/linux-oracle-5.8*
ubuntu/linux-raspi2*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.11*
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<5.4.0-1032.37
5.4.0-1032.37
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-allwinner-5.19*
ubuntu/linux-aws-5.19*
ubuntu/linux-aws-6.2*
ubuntu/linux-azure-5.19*
ubuntu/linux-azure-6.2*
ubuntu/linux-azure-fde-5.19*
ubuntu/linux-azure-fde-6.2*
ubuntu/linux-gcp-5.19*
ubuntu/linux-gcp-6.2*
ubuntu/linux-hwe-5.19*
ubuntu/linux-hwe-6.2*
ubuntu/linux-intel-iot-realtime*
ubuntu/linux-lowlatency-hwe-5.19*
ubuntu/linux-lowlatency-hwe-6.2*
ubuntu/linux-nvidia-6.2*
ubuntu/linux-oem-5.17*
ubuntu/linux-oem-6.0*
ubuntu/linux-oem-6.1*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.19*
ubuntu/linux-starfive-5.19*
ubuntu/linux-starfive-6.2*
ubuntu/linux-raspi-realtime*
ubuntu/linux-vmware*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

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

    Fixed in 4.15.0-1123.136~14.04.1
  2. Upgrade

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

    Fixed in 4.4.0-1143.149
  3. Upgrade

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

    Fixed in 4.4.0-268.302~14.04.1
  4. Upgrade

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

    Fixed in 4.4.0-268.302
  5. Upgrade

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

    Fixed in 4.4.0-1181.196
  6. Upgrade

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

    Fixed in 4.15.0-1111.118~16.04.1
  7. Upgrade

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

    Fixed in 4.15.0-1123.136~16.04.1
  8. Upgrade

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

    Fixed in 4.15.0-1108.122~16.04.1
  9. Upgrade

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

    Fixed in 4.15.0-156.163~16.04.1
  10. Upgrade

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

    Fixed in 4.4.0-1144.155
  11. Upgrade

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

    Fixed in 4.15.0-1080.88~16.04.1
  12. Upgrade

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

    Fixed in 4.4.0-1113.120
  13. Upgrade

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

    Fixed in 4.15.0-156.163
  14. Upgrade

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

    Fixed in 4.15.0-1111.118
  15. Upgrade

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

    Fixed in 5.4.0-1055.58~18.04.1
  16. Upgrade

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

    Fixed in 4.15.0-1123.136
  17. Upgrade

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

    Fixed in 5.4.0-1056.58~18.04.1
  18. Upgrade

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

    Fixed in 4.15.0-1108.122
  19. Upgrade

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

    Fixed in 5.4.0-1051.55~18.04.1
  20. Upgrade

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

    Fixed in 5.4.0-81.91~18.04.1
  21. Upgrade

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

    Fixed in 4.15.0-1099.101
  22. Upgrade

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

    Fixed in 4.15.0-1080.88
  23. Upgrade

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

    Fixed in 5.4.0-1053.57~18.04.1
  24. Upgrade

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

    Fixed in 5.4.0-1042.46~18.04.3
  25. Upgrade

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

    Fixed in 4.15.0-2053.55
  26. Upgrade

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

    Fixed in 4.15.0-2035.39
  27. Upgrade

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

    Fixed in 4.15.0-1069.78
  28. Upgrade

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

    Fixed in 4.15.0-2018.20
  29. Upgrade

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

    Fixed in 5.4.0-81.91
  30. Upgrade

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

    Fixed in 5.4.0-1055.58
  31. Upgrade

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

    Fixed in 5.4.0-1056.58
  32. Upgrade

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

    Fixed in 5.4.0-1019.22
  33. Upgrade

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

    Fixed in 5.4.0-1051.55
  34. Upgrade

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

    Fixed in 5.4.0-1022.23
  35. Upgrade

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

    Fixed in 5.4.0-1045.47
  36. Upgrade

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

    Fixed in 5.4.0-1053.57
  37. Upgrade

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

    Fixed in 5.4.0-1042.46
  38. Upgrade

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

    Fixed in 5.4.0-1069.73+fips2
  39. Upgrade

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

    Fixed in 5.4.0-1073.76+fips1
  40. Upgrade

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

    Fixed in 5.4.0-1032.37
  41. 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 21, 2024
CVE Published
via MITRE·02:19 PM
Data Sourced
via MITRE·02:19 PM
DescriptionSeverity
Data Sourced
via OSV·03:15 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·03:15 PM
RemedyDescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2021-47245?

CVE-2021-47245 has been classified as a medium severity vulnerability.

2

How do I fix CVE-2021-47245?

To fix CVE-2021-47245, update the Linux kernel to a version that contains the patch for this vulnerability.

3

Which Linux kernel versions are affected by CVE-2021-47245?

CVE-2021-47245 affects multiple versions of the Linux kernel from 3.12 up to but not including 5.13.

4

What impact does CVE-2021-47245 have on system security?

CVE-2021-47245 could allow for an out-of-bounds read when parsing TCP options, potentially leading to system instability.

5

Is CVE-2021-47245 exploitable remotely?

Yes, CVE-2021-47245 could be exploited remotely under certain network conditions.

Company

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