CVE-2025-68809: ksmbd: vfs: fix race on m_flags in vfs_cache

Published Jan 13, 2026
·
Updated

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

ksmbd: vfs: fix race on mflags in vfscache

ksmbd maintains delete-on-close and pending-delete state in ksmbdinode->mflags. In vfscache.c this field is accessed under inconsistent locking: some paths read and modify mflags under ci->mlock while others do so without taking the lock at all.

Examples:

- ksmbdqueryinodestatus() and ksmbdinodeclose() use ci->mlock when checking or updating mflags. - ksmbdinodependingdelete(), ksmbdsetinodependingdelete(), ksmbdclearinodependingdelete() and ksmbdfdsetdeleteonclose() used to read and modify mflags without ci->mlock.

This creates a potential data race on mflags when multiple threads open, close and delete the same file concurrently. In the worst case delete-on-close and pending-delete bits can be lost or observed in an inconsistent state, leading to confusing delete semantics (files that stay on disk after delete-on-close, or files that disappear while still in use).

Fix it by:

- Making ksmbdqueryinodestatus() look at mflags under ci->mlock after dropping inodehashlock. - Adding ci->mlock protection to all helpers that read or modify mflags (ksmbdinodependingdelete(), ksmbdsetinodependingdelete(), ksmbdclearinodependingdelete(), ksmbdfdsetdeleteonclose()). - Keeping the existing ci->mlock protection in ksmbdinodeclose(), and moving the actual unlink/xattr removal outside the lock.

This unifies the locking around mflags and removes the data race while preserving the existing delete-on-close behaviour.

Affected Software

198 affected componentsFixes available
Linux Linux kernel
Microsoft azl3 kernel 6.6.119.3-3
Patch available
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*
debian/linux<6.12.69-1
6.12.69-1
debian/linux<6.18.3-1
6.18.3-1
linux/kernel>=5.15.0<6.1.191
6.1.191
linux/kernel>=6.2.0<6.6.120
6.6.120
linux/kernel>=6.7.0<6.12.64
6.12.64
linux/kernel>=6.13.0<6.18.3
6.18.3
debian/linux<=6.1.176-1, <=6.1.190-1
6.12.107-16.12.115-27.2.12-17.2.15-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

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

    Fixed in 6.8.0-1052.55~22.04.1
  2. Upgrade

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

    Fixed in 6.8.0-1059.65~22.04.1
  3. 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
  4. Upgrade

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

    Fixed in 6.8.0-1054.57~22.04.1
  5. Upgrade

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

    Fixed in 6.8.0-110.110~22.04.1
  6. Upgrade

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

    Fixed in 6.8.0-1051.51~22.04.1
  7. 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
  8. Upgrade

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

    Fixed in 6.8.0-1051.54~22.04.1
  9. Upgrade

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

    Fixed in 6.8.0-1049.50~22.04.1
  10. Upgrade

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

    Fixed in 6.8.0-110.110~22.04.1
  11. Upgrade

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

    Fixed in 6.8.1-1047.48~22.04.1
  12. Upgrade

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

    Fixed in 6.8.0-110.110
  13. Upgrade

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

    Fixed in 6.8.0-1052.55
  14. Upgrade

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

    Fixed in 6.17.0-1012.12~24.04.1
  15. Upgrade

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

    Fixed in 6.8.0-1054.60
  16. Upgrade

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

    Fixed in 6.17.0-1013.13~24.04.1
  17. Upgrade

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

    Fixed in 6.8.0-1058.65
  18. Upgrade

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

    Fixed in 6.8.0-1054.57
  19. Upgrade

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

    Fixed in 6.17.0-1012.12~24.04.1
  20. Upgrade

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

    Fixed in 6.8.0-1050.56
  21. Upgrade

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

    Fixed in 6.8.0-1037.40
  22. Upgrade

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

    Fixed in 6.17.0-22.22~24.04.1
  23. Upgrade

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

    Fixed in 6.8.0-1051.51
  24. Upgrade

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

    Fixed in 6.8.0-110.110.1
  25. Upgrade

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

    Fixed in 6.8.0-1051.54
  26. Upgrade

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

    Fixed in 6.17.0-1018.18
  27. Upgrade

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

    Fixed in 6.8.0-1051.54.1
  28. Upgrade

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

    Fixed in 6.8.0-1022.22
  29. Upgrade

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

    Fixed in 6.17.0-1020.20
  30. Upgrade

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

    Fixed in 6.8.0-1049.50
  31. Upgrade

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

    Fixed in 6.17.0-1011.11~24.04.1
  32. Upgrade

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

    Fixed in 6.8.0-1052.56
  33. 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
  34. Upgrade

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

    Fixed in 6.8.0-1028.29
  35. Upgrade

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

    Fixed in 6.8.0-1017.21
  36. Upgrade

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

    Fixed in 6.8.0-2042.43
  37. Upgrade

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

    Fixed in 6.8.1-1047.48
  38. Upgrade

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

    Fixed in 6.17.0-1010.11~24.04.1
  39. Upgrade

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

    Fixed in 6.8.0-1052.55+fips1
  40. Upgrade

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

    Fixed in 6.8.0-1053.59+fips1
  41. Upgrade

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

    Fixed in 6.8.0-110.110+fips2
  42. Upgrade

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

    Fixed in 6.8.0-1054.57+fips1
  43. Upgrade

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

    Fixed in 6.17.0-22.22
  44. Upgrade

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

    Fixed in 6.17.0-1012.12
  45. Upgrade

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

    Fixed in 6.17.0-1013.13
  46. Upgrade

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

    Fixed in 6.17.0-1012.12
  47. Upgrade

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

    Fixed in 6.17.0-1011.11
  48. Upgrade

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

    Fixed in 6.17.0-1013.13
  49. Upgrade

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

    Fixed in 6.17.0-1010.11
  50. Upgrade

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

    Fixed in 6.17.0-22.22.1
  51. Upgrade

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

    Fixed in 6.12.69-1
  52. Upgrade

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

    Fixed in 6.18.3-1
  53. 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 7.2.14-1
  54. Upgrade

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

    Fixed in 6.1.191
  55. Upgrade

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

    Fixed in 6.6.120
  56. Upgrade

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

    Fixed in 6.12.64
  57. Upgrade

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

    Fixed in 6.18.3
  58. Configuration

    Protect all reads and modifications of m_flags with ci->m_lock, including ksmbd_inode_pending_delete(), ksmbd_set_inode_pending_delete(), ksmbd_clear_inode_pending_delete(), ksmbd_fd_set_delete_on_close(), ksmbd_query_inode_status(), and __ksmbd_inode_close(); perform the actual unlink and xattr removal outside the lock.

    Linux kernel ksmbd vfs_cache ci->m_lock protection for ksmbd_inode->m_flags = required for all reads and modifications

Event History

Jan 13, 2026
CVE Published
via MITRE·03:29 PM
Data Sourced
via MITRE·03:29 PM
DescriptionSeverity
Data Sourced
via OSV·03:29 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·04:16 PM
DescriptionSeverity
Jan 15, 2026
Data Sourced
via Microsoft·09:05 AM
DescriptionSeverityWeaknessAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Frequently Asked Questions

1

What is the severity of CVE-2025-68809?

CVE-2025-68809 has been classified with a severity level of high due to potential data integrity issues.

2

How do I fix CVE-2025-68809?

To fix CVE-2025-68809, update to the latest patched version of the Linux kernel where the vulnerability has been addressed.

3

What are the potential impacts of CVE-2025-68809?

The potential impacts of CVE-2025-68809 include data corruption and unexpected behavior in systems utilizing ksmbd.

4

Which versions of the Linux kernel are affected by CVE-2025-68809?

CVE-2025-68809 affects multiple versions of the Linux kernel that use the ksmbd module.

5

Is CVE-2025-68809 being actively exploited?

As of the last assessment, there is no public information indicating active exploitation of CVE-2025-68809.

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