CVE-2025-68786: ksmbd: skip lock-range check on equal size to avoid size==0 underflow

Published Jan 13, 2026
·
Updated

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

ksmbd: skip lock-range check on equal size to avoid size==0 underflow

When size equals the current isize (including 0), the code used to call checklockrange(filp, isize, size - 1, WRITE), which computes size - 1 and can underflow for size==0. Skip the equal case.

Affected Software

190 affected componentsFixes available
Linux Linux kernel
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<6.8.0-1052.55~22.04.1
6.8.0-1052.55~22.04.1
ubuntu/linux-azure*
ubuntu/linux-azure-5.19*
ubuntu/linux-azure-6.2*
ubuntu/linux-azure-6.5*
ubuntu/linux-azure-6.8<6.8.0-1059.65~22.04.1
6.8.0-1059.65~22.04.1
ubuntu/linux-azure-fde*
ubuntu/linux-azure-fde-5.19*
ubuntu/linux-azure-fde-6.2*
ubuntu/linux-azure-fde-6.8<6.8.0-1058.65~22.04.1
6.8.0-1058.65~22.04.1
ubuntu/linux-gcp*
ubuntu/linux-gcp-5.19*
ubuntu/linux-gcp-6.2*
ubuntu/linux-gcp-6.5*
ubuntu/linux-gcp-6.8<6.8.0-1054.57~22.04.1
6.8.0-1054.57~22.04.1
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<6.8.0-110.110~22.04.1
6.8.0-110.110~22.04.1
ubuntu/linux-ibm*
ubuntu/linux-ibm-6.8<6.8.0-1051.51~22.04.1
6.8.0-1051.51~22.04.1
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<6.8.0-110.110.1~22.04.1
6.8.0-110.110.1~22.04.1
ubuntu/linux-nvidia*
ubuntu/linux-nvidia-6.2*
ubuntu/linux-nvidia-6.5*
ubuntu/linux-nvidia-6.8<6.8.0-1051.54~22.04.1
6.8.0-1051.54~22.04.1
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<6.8.0-1049.50~22.04.1
6.8.0-1049.50~22.04.1
ubuntu/linux-raspi*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.19*
ubuntu/linux-riscv-6.5*
ubuntu/linux-riscv-6.8<6.8.0-110.110~22.04.1
6.8.0-110.110~22.04.1
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<6.8.1-1047.48~22.04.1
6.8.1-1047.48~22.04.1
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<6.8.0-110.110
6.8.0-110.110
ubuntu/linux-aws<6.8.0-1052.55
6.8.0-1052.55
ubuntu/linux-aws-6.14*
ubuntu/linux-aws-6.17<6.17.0-1012.12~24.04.1
6.17.0-1012.12~24.04.1
ubuntu/linux-azure<6.8.0-1054.60
6.8.0-1054.60
ubuntu/linux-azure-6.11*
ubuntu/linux-azure-6.14*
ubuntu/linux-azure-6.17<6.17.0-1013.13~24.04.1
6.17.0-1013.13~24.04.1
ubuntu/linux-azure-fde<6.8.0-1058.65
6.8.0-1058.65
ubuntu/linux-azure-fde-6.14*
ubuntu/linux-azure-nvidia*
ubuntu/linux-azure-nvidia-6.14*
ubuntu/linux-gcp<6.8.0-1054.57
6.8.0-1054.57
ubuntu/linux-gcp-6.11*
ubuntu/linux-gcp-6.14*
ubuntu/linux-gcp-6.17<6.17.0-1012.12~24.04.1
6.17.0-1012.12~24.04.1
ubuntu/linux-gke<6.8.0-1050.56
6.8.0-1050.56
ubuntu/linux-gkeop<6.8.0-1037.40
6.8.0-1037.40
ubuntu/linux-hwe-6.11*
ubuntu/linux-hwe-6.14*
ubuntu/linux-hwe-6.17<6.17.0-22.22~24.04.1
6.17.0-22.22~24.04.1
ubuntu/linux-ibm<6.8.0-1051.51
6.8.0-1051.51
ubuntu/linux-lowlatency<6.8.0-110.110.1
6.8.0-110.110.1
ubuntu/linux-lowlatency-hwe-6.11*
ubuntu/linux-nvidia<6.8.0-1051.54
6.8.0-1051.54
ubuntu/linux-nvidia-6.11*
ubuntu/linux-nvidia-6.17<6.17.0-1018.18
6.17.0-1018.18
ubuntu/linux-nvidia-lowlatency<6.8.0-1051.54.1
6.8.0-1051.54.1
ubuntu/linux-nvidia-tegra<6.8.0-1022.22
6.8.0-1022.22
ubuntu/linux-oem-6.11*
ubuntu/linux-oem-6.14*
ubuntu/linux-oem-6.17<6.17.0-1020.20
6.17.0-1020.20
ubuntu/linux-oem-6.8*
ubuntu/linux-oracle<6.8.0-1049.50
6.8.0-1049.50
ubuntu/linux-oracle-6.14*
ubuntu/linux-oracle-6.17<6.17.0-1011.11~24.04.1
6.17.0-1011.11~24.04.1
ubuntu/linux-raspi<6.8.0-1052.56
6.8.0-1052.56
ubuntu/linux-raspi-realtime*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-6.14*
ubuntu/linux-riscv-6.17<6.17.0-22.22.1~24.04.1
6.17.0-22.22.1~24.04.1
ubuntu/linux-xilinx<6.8.0-1028.29
6.8.0-1028.29
ubuntu/linux-bluefield<6.8.0-1017.21
6.8.0-1017.21
ubuntu/linux-raspi-realtime<6.8.0-2042.43
6.8.0-2042.43
ubuntu/linux-realtime<6.8.1-1047.48
6.8.1-1047.48
ubuntu/linux-realtime-6.14*
ubuntu/linux-realtime-6.17<6.17.0-1010.11~24.04.1
6.17.0-1010.11~24.04.1
ubuntu/linux-aws-fips<6.8.0-1052.55+fips1
6.8.0-1052.55+fips1
ubuntu/linux-azure-fips<6.8.0-1053.59+fips1
6.8.0-1053.59+fips1
ubuntu/linux-fips<6.8.0-110.110+fips2
6.8.0-110.110+fips2
ubuntu/linux-gcp-fips<6.8.0-1054.57+fips1
6.8.0-1054.57+fips1
ubuntu/linux<6.17.0-22.22
6.17.0-22.22
ubuntu/linux-aws<6.17.0-1012.12
6.17.0-1012.12
ubuntu/linux-azure<6.17.0-1013.13
6.17.0-1013.13
ubuntu/linux-azure-fde*
ubuntu/linux-gcp<6.17.0-1012.12
6.17.0-1012.12
ubuntu/linux-oracle<6.17.0-1011.11
6.17.0-1011.11
ubuntu/linux-raspi<6.17.0-1013.13
6.17.0-1013.13
ubuntu/linux-realtime<6.17.0-1010.11
6.17.0-1010.11
ubuntu/linux-riscv<6.17.0-22.22.1
6.17.0-22.22.1
debian/linux
6.1.176-16.1.190-16.12.107-16.12.115-27.2.12-17.2.15-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

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

    Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed 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 6.8.0-1052.55~22.04.1
  3. Upgrade

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

    Fixed in 6.8.0-1059.65~22.04.1
  4. Upgrade

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

    Fixed in 6.8.0-1058.65~22.04.1
  5. Upgrade

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

    Fixed in 6.8.0-1054.57~22.04.1
  6. Upgrade

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

    Fixed in 6.8.0-110.110~22.04.1
  7. Upgrade

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

    Fixed in 6.8.0-1051.51~22.04.1
  8. Upgrade

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

    Fixed in 6.8.0-110.110.1~22.04.1
  9. Upgrade

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

    Fixed in 6.8.0-1051.54~22.04.1
  10. Upgrade

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

    Fixed in 6.8.0-1049.50~22.04.1
  11. Upgrade

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

    Fixed in 6.8.0-110.110~22.04.1
  12. Upgrade

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

    Fixed in 6.8.1-1047.48~22.04.1
  13. Upgrade

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

    Fixed in 6.8.0-110.110
  14. Upgrade

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

    Fixed in 6.8.0-1052.55
  15. Upgrade

    Upgrade ubuntu/linux-aws-6.17 to a version that resolves this vulnerability.

    Fixed in 6.17.0-1012.12~24.04.1
  16. Upgrade

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

    Fixed in 6.8.0-1054.60
  17. Upgrade

    Upgrade ubuntu/linux-azure-6.17 to a version that resolves this vulnerability.

    Fixed in 6.17.0-1013.13~24.04.1
  18. Upgrade

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

    Fixed in 6.8.0-1058.65
  19. Upgrade

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

    Fixed in 6.8.0-1054.57
  20. Upgrade

    Upgrade ubuntu/linux-gcp-6.17 to a version that resolves this vulnerability.

    Fixed in 6.17.0-1012.12~24.04.1
  21. Upgrade

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

    Fixed in 6.8.0-1050.56
  22. Upgrade

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

    Fixed in 6.8.0-1037.40
  23. Upgrade

    Upgrade ubuntu/linux-hwe-6.17 to a version that resolves this vulnerability.

    Fixed in 6.17.0-22.22~24.04.1
  24. Upgrade

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

    Fixed in 6.8.0-1051.51
  25. Upgrade

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

    Fixed in 6.8.0-110.110.1
  26. Upgrade

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

    Fixed in 6.8.0-1051.54
  27. Upgrade

    Upgrade ubuntu/linux-nvidia-6.17 to a version that resolves this vulnerability.

    Fixed in 6.17.0-1018.18
  28. Upgrade

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

    Fixed in 6.8.0-1051.54.1
  29. Upgrade

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

    Fixed in 6.8.0-1022.22
  30. Upgrade

    Upgrade ubuntu/linux-oem-6.17 to a version that resolves this vulnerability.

    Fixed in 6.17.0-1020.20
  31. Upgrade

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

    Fixed in 6.8.0-1049.50
  32. Upgrade

    Upgrade ubuntu/linux-oracle-6.17 to a version that resolves this vulnerability.

    Fixed in 6.17.0-1011.11~24.04.1
  33. Upgrade

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

    Fixed in 6.8.0-1052.56
  34. Upgrade

    Upgrade ubuntu/linux-riscv-6.17 to a version that resolves this vulnerability.

    Fixed in 6.17.0-22.22.1~24.04.1
  35. Upgrade

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

    Fixed in 6.8.0-1028.29
  36. Upgrade

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

    Fixed in 6.8.0-1017.21
  37. Upgrade

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

    Fixed in 6.8.0-2042.43
  38. Upgrade

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

    Fixed in 6.8.1-1047.48
  39. Upgrade

    Upgrade ubuntu/linux-realtime-6.17 to a version that resolves this vulnerability.

    Fixed in 6.17.0-1010.11~24.04.1
  40. Upgrade

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

    Fixed in 6.8.0-1052.55+fips1
  41. Upgrade

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

    Fixed in 6.8.0-1053.59+fips1
  42. Upgrade

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

    Fixed in 6.8.0-110.110+fips2
  43. Upgrade

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

    Fixed in 6.8.0-1054.57+fips1
  44. Upgrade

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

    Fixed in 6.17.0-22.22
  45. Upgrade

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

    Fixed in 6.17.0-1012.12
  46. Upgrade

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

    Fixed in 6.17.0-1013.13
  47. Upgrade

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

    Fixed in 6.17.0-1012.12
  48. Upgrade

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

    Fixed in 6.17.0-1011.11
  49. Upgrade

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

    Fixed in 6.17.0-1013.13
  50. Upgrade

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

    Fixed in 6.17.0-1010.11
  51. Upgrade

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

    Fixed in 6.17.0-22.22.1
  52. Compensating control

    In ksmbd, skip the lock-range check when the requested size equals the current i_size, including when both are 0, to avoid evaluating size - 1 and triggering an underflow.

Event History

Jan 13, 2026
CVE Published
via MITRE·03:28 PM
Data Sourced
via MITRE·03:28 PM
Description
Data Sourced
via OSV·04:15 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·04:15 PM
Description
Jan 15, 2026
Data Sourced
via Microsoft·09:06 AM
DescriptionSeverityWeakness

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

1

What is the severity of CVE-2025-68786?

CVE-2025-68786 has been classified with a medium severity level due to potential security implications in the Linux kernel.

2

How do I fix CVE-2025-68786?

To fix CVE-2025-68786, it is recommended to upgrade to the latest stable version of the Linux kernel where the vulnerability is patched.

3

What does CVE-2025-68786 affect?

CVE-2025-68786 affects the ksmbd module in the Linux kernel, specifically relating to lock-range checks.

4

What are the risks associated with CVE-2025-68786?

The risks associated with CVE-2025-68786 include potential data corruption or unauthorized access due to improper lock management.

5

Is CVE-2025-68786 exploitable remotely?

CVE-2025-68786 can be exploited remotely if the affected systems are accessible over the network.

Company

Resources

Contact

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