CVE-2025-39720: ksmbd: fix refcount leak causing resource not released

Published Sep 5, 2025
·
Updated

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

ksmbd: fix refcount leak causing resource not released

When ksmbdconnreleasing(opinfo->conn) returns true,the refcount was not decremented properly, causing a refcount leak that prevents the count from reaching zero and the memory from being released.

Affected Software

185 affected componentsFixes available
Linux Kernel
Microsoft azl3 kernel 6.6.96.2-1
Microsoft azl3 kernel 6.6.96.2-2
Patch available
debian/linux<=6.1.176-1, <=6.1.190-1
6.12.107-16.12.113-17.2.12-17.2.13-1
Linux Linux kernel>=5.15<6.6.103
Linux Linux kernel>=6.7<6.12.44
Linux Linux kernel>=6.13<6.16.4
Linux Linux kernel=6.17-rc1
Linux Linux kernel=6.17-rc2
ubuntu/linux-hwe-edge*
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-5.11*
ubuntu/linux-aws-5.13*
ubuntu/linux-aws-5.15*
ubuntu/linux-aws-5.8*
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-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-5.15*
ubuntu/linux-intel-5.13*
ubuntu/linux-intel-iotg-5.15*
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-5.11*
ubuntu/linux-oracle-5.13*
ubuntu/linux-oracle-5.15*
ubuntu/linux-oracle-5.8*
ubuntu/linux-raspi2*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.11*
ubuntu/linux-riscv-5.15*
ubuntu/linux-riscv-5.8*
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<6.8.0-1046.49~22.04.1
6.8.0-1046.49~22.04.1
ubuntu/linux-azure*
ubuntu/linux-azure-5.19*
ubuntu/linux-azure-6.2*
ubuntu/linux-azure-6.5*
ubuntu/linux-azure-6.8<6.8.0-1051.57~22.04.1
6.8.0-1051.57~22.04.1
ubuntu/linux-azure-fde*
ubuntu/linux-azure-fde-5.19*
ubuntu/linux-azure-fde-6.2*
ubuntu/linux-azure-fde-6.8<6.8.0-1046.53~22.04.1
6.8.0-1046.53~22.04.1
ubuntu/linux-gcp*
ubuntu/linux-gcp-5.19*
ubuntu/linux-gcp-6.2*
ubuntu/linux-gcp-6.5*
ubuntu/linux-gcp-6.8<6.8.0-1047.50~22.04.2
6.8.0-1047.50~22.04.2
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<6.8.0-100.100~22.04.1
6.8.0-100.100~22.04.1
ubuntu/linux-ibm*
ubuntu/linux-ibm-6.8<6.8.0-1044.44~22.04.1
6.8.0-1044.44~22.04.1
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<6.8.0-100.100.1~22.04.1
6.8.0-100.100.1~22.04.1
ubuntu/linux-nvidia*
ubuntu/linux-nvidia-6.2*
ubuntu/linux-nvidia-6.5*
ubuntu/linux-nvidia-6.8<6.8.0-1046.49~22.04.1
6.8.0-1046.49~22.04.1
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<6.8.0-1043.44~22.04.1
6.8.0-1043.44~22.04.1
ubuntu/linux-raspi*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.19*
ubuntu/linux-riscv-6.5*
ubuntu/linux-riscv-6.8<6.8.0-100.100~22.04.1
6.8.0-100.100~22.04.1
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<6.8.1-1041.42~22.04.1
6.8.1-1041.42~22.04.1
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<6.8.0-100.100
6.8.0-100.100
ubuntu/linux-aws<6.8.0-1046.49
6.8.0-1046.49
ubuntu/linux-aws-6.14*
ubuntu/linux-azure<6.8.0-1046.52
6.8.0-1046.52
ubuntu/linux-azure-6.11*
ubuntu/linux-azure-6.14*
ubuntu/linux-azure-fde<6.8.0-1046.53
6.8.0-1046.53
ubuntu/linux-azure-fde-6.14*
ubuntu/linux-azure-nvidia*
ubuntu/linux-azure-nvidia-6.14*
ubuntu/linux-gcp<6.8.0-1047.50
6.8.0-1047.50
ubuntu/linux-gcp-6.11*
ubuntu/linux-gcp-6.14*
ubuntu/linux-gke<6.8.0-1043.48
6.8.0-1043.48
ubuntu/linux-gkeop<6.8.0-1030.33
6.8.0-1030.33
ubuntu/linux-hwe-6.11*
ubuntu/linux-hwe-6.14*
ubuntu/linux-ibm<6.8.0-1044.44
6.8.0-1044.44
ubuntu/linux-intel*
ubuntu/linux-lowlatency<6.8.0-100.100.1
6.8.0-100.100.1
ubuntu/linux-lowlatency-hwe-6.11*
ubuntu/linux-nvidia<6.8.0-1046.49
6.8.0-1046.49
ubuntu/linux-nvidia-6.11*
ubuntu/linux-nvidia-lowlatency<6.8.0-1046.49.1
6.8.0-1046.49.1
ubuntu/linux-nvidia-tegra<6.8.0-1020.20
6.8.0-1020.20
ubuntu/linux-oem-6.11*
ubuntu/linux-oem-6.14*
ubuntu/linux-oem-6.8*
ubuntu/linux-oracle<6.8.0-1043.44
6.8.0-1043.44
ubuntu/linux-oracle-6.14*
ubuntu/linux-raspi<6.8.0-1047.51
6.8.0-1047.51
ubuntu/linux-raspi-realtime*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-6.14*
ubuntu/linux-xilinx<6.8.0-1023.24
6.8.0-1023.24
ubuntu/linux-bluefield<6.8.0-1016.20
6.8.0-1016.20
ubuntu/linux-raspi-realtime<6.8.0-2037.38
6.8.0-2037.38
ubuntu/linux-realtime<6.8.1-1041.42
6.8.1-1041.42
ubuntu/linux-realtime-6.14*
ubuntu/linux-aws-fips<6.8.0-1046.49+fips1
6.8.0-1046.49+fips1
ubuntu/linux-azure-fips<6.8.0-1046.52+fips1
6.8.0-1046.52+fips1
ubuntu/linux-fips<6.8.0-100.100+fips1
6.8.0-100.100+fips1
ubuntu/linux-gcp-fips<6.8.0-1047.50+fips1
6.8.0-1047.50+fips1
ubuntu/linux-azure-fde*
linux/kernel>=5.15.0<6.1.191
6.1.191
linux/kernel>=6.2.0<6.6.103
6.6.103
linux/kernel>=6.7.0<6.12.44
6.12.44
linux/kernel>=6.13.0<6.16.4
6.16.4

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

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

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

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

    Fixed in 6.8.0-1046.49~22.04.1
  3. Upgrade

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

    Fixed in 6.8.0-1051.57~22.04.1
  4. Upgrade

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

    Fixed in 6.8.0-1046.53~22.04.1
  5. Upgrade

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

    Fixed in 6.8.0-1047.50~22.04.2
  6. Upgrade

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

    Fixed in 6.8.0-100.100~22.04.1
  7. Upgrade

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

    Fixed in 6.8.0-1044.44~22.04.1
  8. Upgrade

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

    Fixed in 6.8.0-100.100.1~22.04.1
  9. Upgrade

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

    Fixed in 6.8.0-1046.49~22.04.1
  10. Upgrade

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

    Fixed in 6.8.0-1043.44~22.04.1
  11. Upgrade

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

    Fixed in 6.8.0-100.100~22.04.1
  12. Upgrade

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

    Fixed in 6.8.1-1041.42~22.04.1
  13. Upgrade

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

    Fixed in 6.8.0-100.100
  14. Upgrade

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

    Fixed in 6.8.0-1046.49
  15. Upgrade

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

    Fixed in 6.8.0-1046.52
  16. Upgrade

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

    Fixed in 6.8.0-1046.53
  17. Upgrade

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

    Fixed in 6.8.0-1047.50
  18. Upgrade

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

    Fixed in 6.8.0-1043.48
  19. Upgrade

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

    Fixed in 6.8.0-1030.33
  20. Upgrade

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

    Fixed in 6.8.0-1044.44
  21. Upgrade

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

    Fixed in 6.8.0-100.100.1
  22. Upgrade

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

    Fixed in 6.8.0-1046.49
  23. Upgrade

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

    Fixed in 6.8.0-1046.49.1
  24. Upgrade

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

    Fixed in 6.8.0-1020.20
  25. Upgrade

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

    Fixed in 6.8.0-1043.44
  26. Upgrade

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

    Fixed in 6.8.0-1047.51
  27. Upgrade

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

    Fixed in 6.8.0-1023.24
  28. Upgrade

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

    Fixed in 6.8.0-1016.20
  29. Upgrade

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

    Fixed in 6.8.0-2037.38
  30. Upgrade

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

    Fixed in 6.8.1-1041.42
  31. Upgrade

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

    Fixed in 6.8.0-1046.49+fips1
  32. Upgrade

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

    Fixed in 6.8.0-1046.52+fips1
  33. Upgrade

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

    Fixed in 6.8.0-100.100+fips1
  34. Upgrade

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

    Fixed in 6.8.0-1047.50+fips1
  35. Upgrade

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

    Fixed in 6.1.191
  36. Upgrade

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

    Fixed in 6.6.103
  37. Upgrade

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

    Fixed in 6.12.44
  38. Upgrade

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

    Fixed in 6.16.4

Event History

Sep 5, 2025
CVE Published
via MITRE·05:21 PM
Data Sourced
via MITRE·05:21 PM
DescriptionSeverity
Data Sourced
via OSV·05:21 PM
DescriptionSeverityAffected Software
Event
via OSV·06:15 PM
Data Sourced
via NVD·06:15 PM
RemedyDescriptionSeverityAffected Software
Sep 7, 2025
Data Sourced
via Microsoft·01:06 AM
DescriptionSeverityWeaknessAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

1

What is the severity of CVE-2025-39720?

CVE-2025-39720 has a medium severity level due to the potential for resource leaks in the Linux kernel.

2

How do I fix CVE-2025-39720?

To resolve CVE-2025-39720, update your Linux kernel to the latest version that includes the security patch addressing the refcount leak.

3

What systems are affected by CVE-2025-39720?

CVE-2025-39720 affects the Linux Kernel, specifically instances using the ksmbd SMB server.

4

What impact could CVE-2025-39720 have on my system?

CVE-2025-39720 could lead to resource leaks, resulting in degraded system performance or potential denial of service over time.

5

When was CVE-2025-39720 disclosed?

CVE-2025-39720 was disclosed with patches available in the Linux kernel updates addressing the vulnerability.

Company

Resources

Contact

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