CVE-2025-21946: ksmbd: fix out-of-bounds in parse_sec_desc()

Q: What is the severity of CVE-2025-21946?

CVE-2025-21946 is considered a medium severity vulnerability due to the potential for slab-out-of-bounds issues.

Q: How do I fix CVE-2025-21946?

To mitigate CVE-2025-21946, update to the fixed version of the Linux kernel that addresses the vulnerability.

Q: What component of Linux is affected by CVE-2025-21946?

CVE-2025-21946 affects the ksmbd component of the Linux kernel.

Q: Is CVE-2025-21946 a remote vulnerability?

CVE-2025-21946 is not specifically classified as remote; however, it can potentially be exploited in a networked environment.

Q: What kind of attack can exploit CVE-2025-21946?

Exploitation of CVE-2025-21946 may lead to out-of-bounds access, potentially allowing attackers to cause a denial of service or escalate privileges.

Published Apr 1, 2025

Updated

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

ksmbd: fix out-of-bounds in parsesecdesc()

If osidoffset, gsidoffset and dacloffset could be greater than smbntsd struct size. If it is smaller, It could cause slab-out-of-bounds. And when validating sid, It need to check it included subauth array size.

Affected Software

169 affected componentsFixes available

Linux Linux kernel

Linux Linux kernel>=5.15<6.6.83

Linux Linux kernel>=6.7<6.12.19

Linux Linux kernel>=6.13<6.13.7

Linux Linux kernel=6.14-rc1

Linux Linux kernel=6.14-rc2

Linux Linux kernel=6.14-rc3

Linux Linux kernel=6.14-rc4

Linux Linux kernel=6.14-rc5

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<6.8.0-1039.41~22.04.1

6.8.0-1039.41~22.04.1

ubuntu/linux-azure*

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-6.8<6.8.0-1036.42~22.04.1

6.8.0-1036.42~22.04.1

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<6.8.0-1040.42~22.04.1

6.8.0-1040.42~22.04.1

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<6.8.0-85.85~22.04.1

6.8.0-85.85~22.04.1

ubuntu/linux-ibm*

ubuntu/linux-ibm-6.8<6.8.0-1037.37~22.04.1

6.8.0-1037.37~22.04.1

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<6.8.0-84.84.1~22.04.1

6.8.0-84.84.1~22.04.1

ubuntu/linux-nvidia*

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-nvidia-6.8<6.8.0-1039.42~22.04.1

6.8.0-1039.42~22.04.1

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<6.8.0-1037.38~22.04.1

6.8.0-1037.38~22.04.1

ubuntu/linux-raspi*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-riscv-6.8<6.8.0-84.84~22.04.1

6.8.0-84.84~22.04.1

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<6.8.1-1034.35~22.04.1

6.8.1-1034.35~22.04.1

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<6.8.0-84.84

6.8.0-84.84

ubuntu/linux-aws<6.8.0-1039.41

6.8.0-1039.41

ubuntu/linux-azure<6.8.0-1038.44

6.8.0-1038.44

ubuntu/linux-azure-6.11<6.11.0-1018.18~24.04.1

6.11.0-1018.18~24.04.1

ubuntu/linux-azure-nvidia<6.8.0-1025.27

6.8.0-1025.27

ubuntu/linux-gcp<6.8.0-1040.42

6.8.0-1040.42

ubuntu/linux-gcp-6.11<6.11.0-1016.16~24.04.1

6.11.0-1016.16~24.04.1

ubuntu/linux-gke<6.8.0-1036.40

6.8.0-1036.40

ubuntu/linux-gkeop<6.8.0-1023.25

6.8.0-1023.25

ubuntu/linux-hwe-6.11<6.11.0-28.28~24.04.1

6.11.0-28.28~24.04.1

ubuntu/linux-ibm<6.8.0-1037.37

6.8.0-1037.37

ubuntu/linux-intel*

ubuntu/linux-lowlatency<6.8.0-84.84.1

6.8.0-84.84.1

ubuntu/linux-lowlatency-hwe-6.11<6.11.0-1015.16~24.04.2

6.11.0-1015.16~24.04.2

ubuntu/linux-nvidia<6.8.0-1039.42

6.8.0-1039.42

ubuntu/linux-nvidia-6.11<6.11.0-1012.12

6.11.0-1012.12

ubuntu/linux-nvidia-lowlatency<6.8.0-1039.42.1

6.8.0-1039.42.1

ubuntu/linux-nvidia-tegra<6.8.0-1010.10

6.8.0-1010.10

ubuntu/linux-oem-6.11<6.11.0-1024.24

6.11.0-1024.24

ubuntu/linux-oem-6.8*

ubuntu/linux-oracle<6.8.0-1037.38

6.8.0-1037.38

ubuntu/linux-raspi<6.8.0-1039.43

6.8.0-1039.43

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-xilinx<6.8.0-1018.19

6.8.0-1018.19

ubuntu/linux-raspi-realtime<6.8.0-2030.31

6.8.0-2030.31

ubuntu/linux-realtime<6.8.1-1034.35

6.8.1-1034.35

ubuntu/linux-aws-fips<6.8.0-1039.41+fips1

6.8.0-1039.41+fips1

ubuntu/linux-azure-fips<6.8.0-1040.46+fips1

6.8.0-1040.46+fips1

ubuntu/linux-fips<6.8.0-84.84+fips1

6.8.0-84.84+fips1

ubuntu/linux-gcp-fips<6.8.0-1040.42+fips1

6.8.0-1040.42+fips1

ubuntu/linux-vmware*

debian/linux

6.1.176-16.1.190-16.12.107-16.12.116-17.2.15-17.3.4-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1039.41~22.04.1
Upgrade
Upgrade ubuntu/linux-azure-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1036.42~22.04.1
Upgrade
Upgrade ubuntu/linux-gcp-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1040.42~22.04.1
Upgrade
Upgrade ubuntu/linux-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-85.85~22.04.1
Upgrade
Upgrade ubuntu/linux-ibm-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1037.37~22.04.1
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-84.84.1~22.04.1
Upgrade
Upgrade ubuntu/linux-nvidia-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1039.42~22.04.1
Upgrade
Upgrade ubuntu/linux-oracle-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1037.38~22.04.1
Upgrade
Upgrade ubuntu/linux-riscv-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-84.84~22.04.1
Upgrade
Upgrade ubuntu/linux-realtime-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.1-1034.35~22.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 6.8.0-84.84
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 6.8.0-1039.41
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 6.8.0-1038.44
Upgrade
Upgrade ubuntu/linux-azure-6.11 to a version that resolves this vulnerability.
Fixed in 6.11.0-1018.18~24.04.1
Upgrade
Upgrade ubuntu/linux-azure-nvidia to a version that resolves this vulnerability.
Fixed in 6.8.0-1025.27
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 6.8.0-1040.42
Upgrade
Upgrade ubuntu/linux-gcp-6.11 to a version that resolves this vulnerability.
Fixed in 6.11.0-1016.16~24.04.1
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 6.8.0-1036.40
Upgrade
Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 6.8.0-1023.25
Upgrade
Upgrade ubuntu/linux-hwe-6.11 to a version that resolves this vulnerability.
Fixed in 6.11.0-28.28~24.04.1
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 6.8.0-1037.37
Upgrade
Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 6.8.0-84.84.1
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-6.11 to a version that resolves this vulnerability.
Fixed in 6.11.0-1015.16~24.04.2
Upgrade
Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 6.8.0-1039.42
Upgrade
Upgrade ubuntu/linux-nvidia-6.11 to a version that resolves this vulnerability.
Fixed in 6.11.0-1012.12
Upgrade
Upgrade ubuntu/linux-nvidia-lowlatency to a version that resolves this vulnerability.
Fixed in 6.8.0-1039.42.1
Upgrade
Upgrade ubuntu/linux-nvidia-tegra to a version that resolves this vulnerability.
Fixed in 6.8.0-1010.10
Upgrade
Upgrade ubuntu/linux-oem-6.11 to a version that resolves this vulnerability.
Fixed in 6.11.0-1024.24
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 6.8.0-1037.38
Upgrade
Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 6.8.0-1039.43
Upgrade
Upgrade ubuntu/linux-xilinx to a version that resolves this vulnerability.
Fixed in 6.8.0-1018.19
Upgrade
Upgrade ubuntu/linux-raspi-realtime to a version that resolves this vulnerability.
Fixed in 6.8.0-2030.31
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 6.8.1-1034.35
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1039.41+fips1
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1040.46+fips1
Upgrade
Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-84.84+fips1
Upgrade
Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1040.42+fips1
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 6.12.116-1Fixed in 7.2.15-1Fixed in 7.3.4-1
Compensating control
Validate that a SID includes a valid subauthority array size, and reject security descriptors when osidoffset, gsidoffset, or dacloffset exceeds the smb_ntsd structure size to prevent slab out-of-bounds access.

Event History

Apr 1, 2025

CVE Published

via MITRE·03:41 PM

Data Sourced

via MITRE·03:41 PM

DescriptionSeverity

Data Sourced

via OSV·04:15 PM

DescriptionSeverityAffected Software

Data Sourced

via NVD·04:15 PM

RemedyDescriptionSeverityWeaknessAffected Software

Nov 1, 2025

Data Sourced

via Microsoft·01:02 AM

DescriptionSeverityWeakness

Parent advisories

This vulnerability appears in the following advisories.

DSA-6127

Peer vulnerabilities

Found alongside the following vulnerabilities.

DLA-4476-1

Frequently Asked Questions

What is the severity of CVE-2025-21946?

CVE-2025-21946 is considered a medium severity vulnerability due to the potential for slab-out-of-bounds issues.

How do I fix CVE-2025-21946?

To mitigate CVE-2025-21946, update to the fixed version of the Linux kernel that addresses the vulnerability.

What component of Linux is affected by CVE-2025-21946?

CVE-2025-21946 affects the ksmbd component of the Linux kernel.

Is CVE-2025-21946 a remote vulnerability?

CVE-2025-21946 is not specifically classified as remote; however, it can potentially be exploited in a networked environment.

What kind of attack can exploit CVE-2025-21946?

Exploitation of CVE-2025-21946 may lead to out-of-bounds access, potentially allowing attackers to cause a denial of service or escalate privileges.

CVE-2025-21946: ksmbd: fix out-of-bounds in parse_sec_desc()

Affected Software

Remediation

Event History

Parent advisories

Peer vulnerabilities

Frequently Asked Questions

What is the severity of CVE-2025-21946?

How do I fix CVE-2025-21946?

What component of Linux is affected by CVE-2025-21946?

Is CVE-2025-21946 a remote vulnerability?

What kind of attack can exploit CVE-2025-21946?

Company

Resources

Contact