CVE-2025-38191: Linux Kernel ksmbd destroy_previous_session Null Pointer Dereference Denial-of-Service Vulnerability

Published Jul 4, 2025
·
Updated

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

ksmbd: fix null pointer dereference in destroyprevioussession

If client set ->PreviousSessionId on kerberos session setup stage, NULL pointer dereference error will happen. Since sess->user is not set yet, It can pass the user argument as NULL to destroyprevioussession. sess->user will be set in ksmbdkrb5authenticate(). So this patch move calling destroyprevioussession() after ksmbdkrb5authenticate().

Other sources

This vulnerability allows remote attackers to create a denial-of-service condition on affected installations of the Linux Kernel. Authentication is not required to exploit this vulnerability. The specific flaw exists within the destroyprevioussession function. The issue results from the lack of proper validation of a pointer prior to accessing it. An attacker can leverage this vulnerability to create a denial-of-service condition on the system.

— ZDI

Affected Software

182 affected componentsFixes available
Linux Kernel
Microsoft cbl2 kernel 5.15.186.1-1
Microsoft azl3 kernel 6.6.92.2-2
Patch available
Linux Kernel
Linux Linux kernel>=5.15<6.1.142
Linux Linux kernel>=6.2<6.6.95
Linux Linux kernel>=6.7<6.12.35
Linux Linux kernel>=6.13<6.15.4
Linux Linux kernel=6.16-rc1
Linux Linux kernel=6.16-rc2
Debian Debian Linux=11.0
debian/linux
6.1.176-16.1.190-16.12.107-16.12.113-17.2.12-17.2.13-1
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<6.14.0-1015.15~24.04.1
6.14.0-1015.15~24.04.1
ubuntu/linux-azure<6.8.0-1046.52
6.8.0-1046.52
ubuntu/linux-azure-6.11*
ubuntu/linux-azure-6.14<6.14.0-1014.14~24.04.1
6.14.0-1014.14~24.04.1
ubuntu/linux-azure-fde<6.8.0-1046.53
6.8.0-1046.53
ubuntu/linux-azure-nvidia*
ubuntu/linux-azure-nvidia-6.14<6.14.0-1007.7
6.14.0-1007.7
ubuntu/linux-gcp<6.8.0-1047.50
6.8.0-1047.50
ubuntu/linux-gcp-6.11*
ubuntu/linux-gcp-6.14<6.14.0-1018.19~24.04.1
6.14.0-1018.19~24.04.1
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-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<6.14.0-1014.14
6.14.0-1014.14
ubuntu/linux-oem-6.8*
ubuntu/linux-oracle<6.8.0-1043.44
6.8.0-1043.44
ubuntu/linux-oracle-6.14<6.14.0-1015.15~24.04.1
6.14.0-1015.15~24.04.1
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<6.14.0-34.34.1~24.04.1
6.14.0-34.34.1~24.04.1
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<6.14.0-1014.14~24.04.1
6.14.0-1014.14~24.04.1
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*

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 6.8.0-1046.49~22.04.1
  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-aws-6.14 to a version that resolves this vulnerability.

    Fixed in 6.14.0-1015.15~24.04.1
  16. Upgrade

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

    Fixed in 6.8.0-1046.52
  17. Upgrade

    Upgrade ubuntu/linux-azure-6.14 to a version that resolves this vulnerability.

    Fixed in 6.14.0-1014.14~24.04.1
  18. Upgrade

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

    Fixed in 6.8.0-1046.53
  19. Upgrade

    Upgrade ubuntu/linux-azure-nvidia-6.14 to a version that resolves this vulnerability.

    Fixed in 6.14.0-1007.7
  20. Upgrade

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

    Fixed in 6.8.0-1047.50
  21. Upgrade

    Upgrade ubuntu/linux-gcp-6.14 to a version that resolves this vulnerability.

    Fixed in 6.14.0-1018.19~24.04.1
  22. Upgrade

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

    Fixed in 6.8.0-1043.48
  23. Upgrade

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

    Fixed in 6.8.0-1030.33
  24. Upgrade

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

    Fixed in 6.8.0-1044.44
  25. Upgrade

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

    Fixed in 6.8.0-100.100.1
  26. Upgrade

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

    Fixed in 6.8.0-1046.49
  27. Upgrade

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

    Fixed in 6.8.0-1046.49.1
  28. Upgrade

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

    Fixed in 6.8.0-1020.20
  29. Upgrade

    Upgrade ubuntu/linux-oem-6.14 to a version that resolves this vulnerability.

    Fixed in 6.14.0-1014.14
  30. Upgrade

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

    Fixed in 6.8.0-1043.44
  31. Upgrade

    Upgrade ubuntu/linux-oracle-6.14 to a version that resolves this vulnerability.

    Fixed in 6.14.0-1015.15~24.04.1
  32. Upgrade

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

    Fixed in 6.8.0-1047.51
  33. Upgrade

    Upgrade ubuntu/linux-riscv-6.14 to a version that resolves this vulnerability.

    Fixed in 6.14.0-34.34.1~24.04.1
  34. Upgrade

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

    Fixed in 6.8.0-1023.24
  35. Upgrade

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

    Fixed in 6.8.0-1016.20
  36. Upgrade

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

    Fixed in 6.8.0-2037.38
  37. Upgrade

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

    Fixed in 6.8.1-1041.42
  38. Upgrade

    Upgrade ubuntu/linux-realtime-6.14 to a version that resolves this vulnerability.

    Fixed in 6.14.0-1014.14~24.04.1
  39. Upgrade

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

    Fixed in 6.8.0-1046.49+fips1
  40. Upgrade

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

    Fixed in 6.8.0-1046.52+fips1
  41. Upgrade

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

    Fixed in 6.8.0-100.100+fips1
  42. Upgrade

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

    Fixed in 6.8.0-1047.50+fips1

Event History

Jul 4, 2025
CVE Published
via MITRE·01:37 PM
Data Sourced
via MITRE·01:37 PM
DescriptionSeverity
Data Sourced
via OSV·02:15 PM
DescriptionSeverityAffected Software
Event
via OSV·02:15 PM
Data Sourced
via NVD·02:15 PM
RemedyDescriptionSeverityWeaknessAffected Software
Jul 17, 2025
Advisory Published
via ZDI·12:00 AM
Data Sourced
via ZDI·12:00 AM
DescriptionSeverityAffected Software
Aug 7, 2025
Data Sourced
via Microsoft·12:00 AM
DescriptionSeverityWeaknessAffected Software

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-2025-38191?

CVE-2025-38191 is classified as a high-severity vulnerability due to the potential for a null pointer dereference.

2

How do I fix CVE-2025-38191?

To fix CVE-2025-38191, you should update the Linux kernel to the latest patched version provided by your distribution.

3

Who is affected by CVE-2025-38191?

CVE-2025-38191 affects users of the Linux kernel who utilize ksmbd for Kerberos session setups.

4

What type of vulnerability is CVE-2025-38191?

CVE-2025-38191 is a null pointer dereference vulnerability found in the ksmbd component of the Linux kernel.

5

What could happen if CVE-2025-38191 is exploited?

Exploitation of CVE-2025-38191 can lead to a crash of the affected application or system due to the null pointer dereference.

Company

Resources

Contact

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