CVE-2025-21768: net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels

Published Feb 27, 2025
·
Updated

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

net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels

Some lwtunnels have a dst cache for post-transformation dst. If the packet destination did not change we may end up recording a reference to the lwtunnel in its own cache, and the lwtunnel state will never be freed.

Discovered by the ioam6.sh test, kmemleak was recently fixed to catch per-cpu memory leaks. I'm not sure if rpl and seg6 can actually hit this, but in principle I don't see why not.

Affected Software

228 affected componentsFixes available
Linux Kernel
All of the following
azurelinux/kernel=6.6.119.3-1
Microsoft Azure Linux=3.0
All of the following
azurelinux/kernel=6.6.117.1-1
Microsoft Azure Linux=3.0
All of the following
azurelinux/kernel=6.6.104.2-4
Microsoft Azure Linux=3.0
All of the following
azurelinux/kernel=5.15.186.1-1
Microsoft CBL-Mariner=2.0
All of the following
azurelinux/kernel=6.6.112.1-2
Microsoft Azure Linux=3.0
All of the following
azurelinux/kernel=6.6.96.2-2
Microsoft Azure Linux=3.0
All of the following
azurelinux/kernel=6.6.96.2-1
Microsoft Azure Linux=3.0
Linux Linux kernel>=4.10<6.12.16
Linux Linux kernel>=6.13<6.13.4
Linux Linux kernel=6.14-rc1
debian/linux*
debian/linux<6.12.16-1
6.12.16-1
debian/linux<6.12.16-1
6.12.16-1
linux/kernel>=4.10.0<6.1.191
6.1.191
linux/kernel>=6.2.0<6.6.160
6.6.160
linux/kernel>=6.7.0<6.12.16
6.12.16
linux/kernel>=6.13.0<6.13.4
6.13.4
debian/linux<=6.1.176-1, <=6.1.190-1
6.12.107-16.12.115-27.2.15-1
ubuntu/linux-azure*
ubuntu/linux-aws-hwe*
ubuntu/linux-azure*
ubuntu/linux-gcp*
ubuntu/linux-hwe*
ubuntu/linux-hwe-edge*
ubuntu/linux-oracle*
ubuntu/linux*
ubuntu/linux-aws*
ubuntu/linux-aws-5.0*
ubuntu/linux-aws-5.3*
ubuntu/linux-aws-5.4*
ubuntu/linux-azure*
ubuntu/linux-azure-4.15*
ubuntu/linux-azure-5.3*
ubuntu/linux-azure-5.4*
ubuntu/linux-azure-edge*
ubuntu/linux-gcp*
ubuntu/linux-gcp-4.15*
ubuntu/linux-gcp-5.3*
ubuntu/linux-gcp-5.4*
ubuntu/linux-gke-4.15*
ubuntu/linux-gke-5.4*
ubuntu/linux-gkeop-5.4*
ubuntu/linux-hwe*
ubuntu/linux-hwe-5.4*
ubuntu/linux-hwe-edge*
ubuntu/linux-ibm-5.4*
ubuntu/linux-kvm*
ubuntu/linux-oem*
ubuntu/linux-oracle*
ubuntu/linux-oracle-5.0*
ubuntu/linux-oracle-5.3*
ubuntu/linux-oracle-5.4*
ubuntu/linux-raspi-5.4*
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*
ubuntu/linux-aws*
ubuntu/linux-aws-5.11*
ubuntu/linux-aws-5.13*
ubuntu/linux-aws-5.15*
ubuntu/linux-aws-5.8*
ubuntu/linux-azure*
ubuntu/linux-azure-5.11*
ubuntu/linux-azure-5.13*
ubuntu/linux-azure-5.15*
ubuntu/linux-azure-5.8*
ubuntu/linux-azure-fde*
ubuntu/linux-azure-fde-5.15*
ubuntu/linux-bluefield*
ubuntu/linux-gcp*
ubuntu/linux-gcp-5.11*
ubuntu/linux-gcp-5.13*
ubuntu/linux-gcp-5.15*
ubuntu/linux-gcp-5.8*
ubuntu/linux-gke*
ubuntu/linux-gke-5.15*
ubuntu/linux-gkeop*
ubuntu/linux-gkeop-5.15*
ubuntu/linux-hwe-5.11*
ubuntu/linux-hwe-5.13*
ubuntu/linux-hwe-5.15*
ubuntu/linux-hwe-5.8*
ubuntu/linux-ibm*
ubuntu/linux-ibm-5.15*
ubuntu/linux-intel-5.13*
ubuntu/linux-intel-iotg-5.15*
ubuntu/linux-iot*
ubuntu/linux-kvm*
ubuntu/linux-lowlatency-hwe-5.15*
ubuntu/linux-nvidia-tegra-5.15*
ubuntu/linux-oem-5.10*
ubuntu/linux-oem-5.13*
ubuntu/linux-oem-5.6*
ubuntu/linux-oracle*
ubuntu/linux-oracle-5.11*
ubuntu/linux-oracle-5.13*
ubuntu/linux-oracle-5.15*
ubuntu/linux-oracle-5.8*
ubuntu/linux-raspi*
ubuntu/linux-raspi2*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.11*
ubuntu/linux-riscv-5.15*
ubuntu/linux-riscv-5.8*
ubuntu/linux-xilinx-zynqmp*
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*
ubuntu/linux-allwinner-5.19*
ubuntu/linux-aws*
ubuntu/linux-aws-5.19*
ubuntu/linux-aws-6.2*
ubuntu/linux-aws-6.5*
ubuntu/linux-aws-6.8<6.8.0-1035.37~22.04.1
6.8.0-1035.37~22.04.1
ubuntu/linux-azure*
ubuntu/linux-azure-5.19*
ubuntu/linux-azure-6.2*
ubuntu/linux-azure-6.5*
ubuntu/linux-azure-6.8<6.8.0-1034.39~22.04.1
6.8.0-1034.39~22.04.1
ubuntu/linux-azure-fde*
ubuntu/linux-azure-fde-5.19*
ubuntu/linux-azure-fde-6.2*
ubuntu/linux-gcp*
ubuntu/linux-gcp-5.19*
ubuntu/linux-gcp-6.2*
ubuntu/linux-gcp-6.5*
ubuntu/linux-gcp-6.8<6.8.0-1036.38~22.04.1
6.8.0-1036.38~22.04.1
ubuntu/linux-gke*
ubuntu/linux-gkeop*
ubuntu/linux-hwe-5.19*
ubuntu/linux-hwe-6.2*
ubuntu/linux-hwe-6.5*
ubuntu/linux-hwe-6.8<6.8.0-78.78~22.04.1
6.8.0-78.78~22.04.1
ubuntu/linux-ibm*
ubuntu/linux-ibm-6.8<6.8.0-1033.33~22.04.1
6.8.0-1033.33~22.04.1
ubuntu/linux-intel-iot-realtime*
ubuntu/linux-intel-iotg*
ubuntu/linux-kvm*
ubuntu/linux-lowlatency*
ubuntu/linux-lowlatency-hwe-5.19*
ubuntu/linux-lowlatency-hwe-6.2*
ubuntu/linux-lowlatency-hwe-6.5*
ubuntu/linux-lowlatency-hwe-6.8<6.8.0-78.78.1~22.04.1
6.8.0-78.78.1~22.04.1
ubuntu/linux-nvidia*
ubuntu/linux-nvidia-6.2*
ubuntu/linux-nvidia-6.5*
ubuntu/linux-nvidia-6.8<6.8.0-1035.38~22.04.1
6.8.0-1035.38~22.04.1
ubuntu/linux-nvidia-tegra*
ubuntu/linux-nvidia-tegra-igx*
ubuntu/linux-oem-5.17*
ubuntu/linux-oem-6.0*
ubuntu/linux-oem-6.1*
ubuntu/linux-oem-6.5*
ubuntu/linux-oracle*
ubuntu/linux-oracle-6.5*
ubuntu/linux-oracle-6.8<6.8.0-1032.33~22.04.1
6.8.0-1032.33~22.04.1
ubuntu/linux-raspi*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.19*
ubuntu/linux-riscv-6.5*
ubuntu/linux-riscv-6.8<6.8.0-78.78~22.04.1
6.8.0-78.78~22.04.1
ubuntu/linux-starfive-5.19*
ubuntu/linux-starfive-6.2*
ubuntu/linux-starfive-6.5*
ubuntu/linux-xilinx-zynqmp*
ubuntu/linux-bluefield*
ubuntu/linux-intel-iot-realtime*
ubuntu/linux-realtime*
ubuntu/linux-realtime-6.8<6.8.1-1030.31~22.04.1
6.8.1-1030.31~22.04.1
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<6.8.0-78.78
6.8.0-78.78
ubuntu/linux-aws<6.8.0-1035.37
6.8.0-1035.37
ubuntu/linux-azure<6.8.0-1034.39
6.8.0-1034.39
ubuntu/linux-azure-6.11<6.11.0-1015.15~24.04.1
6.11.0-1015.15~24.04.1
ubuntu/linux-azure-nvidia<6.8.0-1022.23
6.8.0-1022.23
ubuntu/linux-gcp<6.8.0-1036.38
6.8.0-1036.38
ubuntu/linux-gcp-6.11<6.11.0-1015.15~24.04.1
6.11.0-1015.15~24.04.1
ubuntu/linux-gke<6.8.0-1032.36
6.8.0-1032.36
ubuntu/linux-gkeop<6.8.0-1019.21
6.8.0-1019.21
ubuntu/linux-hwe-6.11<6.11.0-26.26~24.04.1
6.11.0-26.26~24.04.1
ubuntu/linux-ibm<6.8.0-1033.33
6.8.0-1033.33
ubuntu/linux-intel*
ubuntu/linux-lowlatency<6.8.0-78.78.1
6.8.0-78.78.1
ubuntu/linux-lowlatency-hwe-6.11<6.11.0-1014.15~24.04.1
6.11.0-1014.15~24.04.1
ubuntu/linux-nvidia<6.8.0-1035.38
6.8.0-1035.38
ubuntu/linux-nvidia-6.11<6.11.0-1010.10
6.11.0-1010.10
ubuntu/linux-nvidia-lowlatency<6.8.0-1035.38.1
6.8.0-1035.38.1
ubuntu/linux-nvidia-tegra<6.8.0-1009.9
6.8.0-1009.9
ubuntu/linux-oem-6.11<6.11.0-1022.22
6.11.0-1022.22
ubuntu/linux-oem-6.8*
ubuntu/linux-oracle<6.8.0-1032.33
6.8.0-1032.33
ubuntu/linux-raspi<6.8.0-1035.39
6.8.0-1035.39
ubuntu/linux-raspi-realtime*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-xilinx<6.8.0-1017.18
6.8.0-1017.18
ubuntu/linux-raspi-realtime<6.8.0-2028.29
6.8.0-2028.29
ubuntu/linux-realtime<6.8.1-1030.31
6.8.1-1030.31
ubuntu/linux-fips<6.8.0-78.78+fips1
6.8.0-78.78+fips1
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 6.12.16-1
  2. Upgrade

    Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1035.37~22.04.1
  3. Upgrade

    Upgrade ubuntu/linux-azure-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1034.39~22.04.1
  4. Upgrade

    Upgrade ubuntu/linux-gcp-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1036.38~22.04.1
  5. Upgrade

    Upgrade ubuntu/linux-hwe-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-78.78~22.04.1
  6. Upgrade

    Upgrade ubuntu/linux-ibm-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1033.33~22.04.1
  7. Upgrade

    Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-78.78.1~22.04.1
  8. Upgrade

    Upgrade ubuntu/linux-nvidia-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1035.38~22.04.1
  9. Upgrade

    Upgrade ubuntu/linux-oracle-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-1032.33~22.04.1
  10. Upgrade

    Upgrade ubuntu/linux-riscv-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.0-78.78~22.04.1
  11. Upgrade

    Upgrade ubuntu/linux-realtime-6.8 to a version that resolves this vulnerability.

    Fixed in 6.8.1-1030.31~22.04.1
  12. Upgrade

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

    Fixed in 6.8.0-78.78
  13. Upgrade

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

    Fixed in 6.8.0-1035.37
  14. Upgrade

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

    Fixed in 6.8.0-1034.39
  15. Upgrade

    Upgrade ubuntu/linux-azure-6.11 to a version that resolves this vulnerability.

    Fixed in 6.11.0-1015.15~24.04.1
  16. Upgrade

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

    Fixed in 6.8.0-1022.23
  17. Upgrade

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

    Fixed in 6.8.0-1036.38
  18. Upgrade

    Upgrade ubuntu/linux-gcp-6.11 to a version that resolves this vulnerability.

    Fixed in 6.11.0-1015.15~24.04.1
  19. Upgrade

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

    Fixed in 6.8.0-1032.36
  20. Upgrade

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

    Fixed in 6.8.0-1019.21
  21. Upgrade

    Upgrade ubuntu/linux-hwe-6.11 to a version that resolves this vulnerability.

    Fixed in 6.11.0-26.26~24.04.1
  22. Upgrade

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

    Fixed in 6.8.0-1033.33
  23. Upgrade

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

    Fixed in 6.8.0-78.78.1
  24. Upgrade

    Upgrade ubuntu/linux-lowlatency-hwe-6.11 to a version that resolves this vulnerability.

    Fixed in 6.11.0-1014.15~24.04.1
  25. Upgrade

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

    Fixed in 6.8.0-1035.38
  26. Upgrade

    Upgrade ubuntu/linux-nvidia-6.11 to a version that resolves this vulnerability.

    Fixed in 6.11.0-1010.10
  27. Upgrade

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

    Fixed in 6.8.0-1035.38.1
  28. Upgrade

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

    Fixed in 6.8.0-1009.9
  29. Upgrade

    Upgrade ubuntu/linux-oem-6.11 to a version that resolves this vulnerability.

    Fixed in 6.11.0-1022.22
  30. Upgrade

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

    Fixed in 6.8.0-1032.33
  31. Upgrade

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

    Fixed in 6.8.0-1035.39
  32. Upgrade

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

    Fixed in 6.8.0-1017.18
  33. Upgrade

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

    Fixed in 6.8.0-2028.29
  34. Upgrade

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

    Fixed in 6.8.1-1030.31
  35. Upgrade

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

    Fixed in 6.8.0-78.78+fips1
  36. Upgrade

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

    Fixed in 6.1.191
  37. Upgrade

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

    Fixed in 6.6.160
  38. Upgrade

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

    Fixed in 6.12.16
  39. Upgrade

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

    Fixed in 6.13.4
  40. Upgrade

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

    Fixed in 6.12.107-1Fixed in 6.12.115-2Fixed in 7.2.15-1

Event History

Feb 27, 2025
CVE Published
via MITRE·02:18 AM
Data Sourced
via MITRE·02:18 AM
Description
Data Sourced
via OSV·02:18 AM
DescriptionAffected Software
Data Sourced
via NVD·03:15 AM
RemedyDescriptionSeverityWeaknessAffected Software
Sep 3, 2025
Data Sourced
via Microsoft·10:19 PM
DescriptionSeverityWeaknessAffected Software
Nov 11, 2026
Data Sourced
via OSV·09:38 AM
Severity

Frequently Asked Questions

1

What is the severity of CVE-2025-21768?

CVE-2025-21768 has been classified with a severity level that necessitates immediate attention to mitigate potential system vulnerabilities.

2

How do I fix CVE-2025-21768?

To address CVE-2025-21768, ensure you update the Linux kernel to the latest stable version where the vulnerability has been resolved.

3

What impact does CVE-2025-21768 have on system security?

CVE-2025-21768 can lead to potential security risks involving reference loops within specific network lwtunnels, affecting data integrity.

4

Which versions of the Linux kernel are affected by CVE-2025-21768?

CVE-2025-21768 affects multiple versions of the Linux kernel prior to the patch that resolves this issue.

5

Is CVE-2025-21768 exploitable by remote attackers?

CVE-2025-21768 may introduce vulnerabilities that could potentially be exploited by remote attackers under certain conditions.

Company

Resources

Contact

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