Description
A flaw was found in the Linux kernel's ksmbd, a high-performance in-kernel SMB server. The specific flaw exists within the processing of SMB2_LOGOFF and SMB2_CLOSE commands. The issue results from the lack of proper locking when performing operations on an object. An attacker can leverage this vulnerability to execute code in the context of the kernel.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | kernel | — | 6.4-rc1 |
| Red Hat | Red Hat Enterprise Linux 6 | — | — |
| Red Hat | Red Hat Enterprise Linux 7 | — | — |
| Red Hat | Red Hat Enterprise Linux 8 | — | — |
| Red Hat | Red Hat Enterprise Linux 9 | — | — |
| Fedora | Fedora | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 6.3.7-1 | — |
| Debian 13 | linux | 6.3.7-1 | — |
| Debian 12 | linux | 6.1.37-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 22.04 LTS | linux-bluefield | 5.15.0-1040.42 | — |
| Ubuntu 24.04 LTS | linux-raspi-realtime | No fix yet | — |
| Ubuntu 22.04 LTS | linux +1 | 5.15.0-102.112 | USN-6725-1 |
| Ubuntu 22.04 LTS | linux-aws | 5.15.0-1057.63 | USN-6725-2 |
| Ubuntu 22.04 LTS | linux-aws-6.2 | 6.2.0-1011.11~22.04.1 | USN-6338-1 |
| Ubuntu 22.04 LTS | linux-azure | 5.15.0-1060.69 | USN-6725-1 |
| Ubuntu 22.04 LTS | linux-azure-fde | 5.15.0-1060.69.1 | USN-6725-1 |
| Ubuntu 22.04 LTS | linux-gcp | 5.15.0-1055.63 | USN-6725-1 |
| Ubuntu 22.04 LTS | linux-gcp-6.2 | 6.2.0-1013.13~22.04.1 | USN-6338-2 |
| Ubuntu 22.04 LTS | linux-gke +1 | 5.15.0-1054.59 | USN-6725-1 |
| Ubuntu 22.04 LTS | linux-gkeop | 5.15.0-1040.46 | USN-6725-1 |
| Ubuntu 22.04 LTS | linux-hwe-6.2 | 6.2.0-32.32~22.04.1 | USN-6338-1 |
| Ubuntu 22.04 LTS | linux-ibm +1 | 5.15.0-1050.53 | USN-6725-1 |
| Ubuntu 22.04 LTS | linux-intel-iotg | 5.15.0-1052.58 | USN-6725-1 |
| Ubuntu 22.04 LTS | linux-lowlatency-hwe-6.2 | 6.2.0-1012.12~22.04.1 | USN-6338-1 |
| Ubuntu 22.04 LTS | linux-nvidia | 5.15.0-1048.48 | USN-6725-1 |
| Ubuntu 22.04 LTS | linux-nvidia-6.2 | 6.2.0-1010.10 | — |
| Ubuntu 22.04 LTS | linux-nvidia-tegra | 5.15.0-1025.25 | — |
| Ubuntu 22.04 LTS | linux-nvidia-tegra-igx | 5.15.0-1012.12 | — |
| Ubuntu 22.04 LTS | linux-oem-6.1 | 6.1.0-1014.14 | — |
| Ubuntu 22.04 LTS | linux-oracle | 5.15.0-1055.61 | USN-6725-1 |
| Ubuntu 22.04 LTS | linux-riscv +12 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-xilinx-zynqmp | 5.15.0-1030.34 | — |
| Ubuntu 20.04 LTS | linux-aws-5.15 | 5.15.0-1057.63~20.04.1 | USN-6725-2 |
| Ubuntu 20.04 LTS | linux-azure-5.15 | 5.15.0-1060.69~20.04.1 | USN-6725-1 |
| Ubuntu 20.04 LTS | linux-azure-fde-5.15 | 5.15.0-1060.69~20.04.1.1 | USN-6725-1 |
| Ubuntu 20.04 LTS | linux-gcp-5.15 | 5.15.0-1055.63~20.04.1 | USN-6725-1 |
| Ubuntu 20.04 LTS | linux-gke +25 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-gkeop-5.15 | 5.15.0-1040.46~20.04.1 | USN-6725-1 |
| Ubuntu 20.04 LTS | linux-hwe-5.15 +1 | 5.15.0-102.112~20.04.1 | USN-6725-1 |
| Ubuntu 20.04 LTS | linux-ibm-5.15 | 5.15.0-1050.53~20.04.1 | USN-6725-1 |
| Ubuntu 20.04 LTS | linux-intel-iotg-5.15 | 5.15.0-1052.58~20.04.1 | USN-6725-1 |
| Ubuntu 20.04 LTS | linux-nvidia-tegra-5.15 | 5.15.0-1025.25~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-oracle-5.15 | 5.15.0-1055.61~20.04.1 | USN-6725-1 |
| Ubuntu 20.04 LTS | linux-riscv-5.15 | 5.15.0-1053.57~20.04.1 | — |
| Ubuntu 18.04 LTS | linux-gcp +13 | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-intel-iot-realtime | 5.15.0-1050.52 | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime | 5.15.0-1058.66 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-aws-fips | 5.15.0-1057.63+fips1 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-azure-fips | 5.15.0-1060.69+fips1 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-fips | 5.15.0-102.112+fips1 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-gcp-fips | 5.15.0-1055.63+fips2 | — |
| Ubuntu Pro FIPS-preview 22.04 LTS | linux-fips +3 | No fix yet | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 2 (CBL-Mariner) | hyperv-daemons | 5.15.145.2-1 | — |
| Azure Linux 2 (CBL-Mariner) | kernel | 5.15.135.1-2 | — |
Advisories 5
- USN-6725-1 linux, linux-azure, linux-azure-5.15, linux-azure-fde, linux-azure-fde-5.15, linux-gcp, linux-gcp-5.15, linux-gke, linux-gkeop, linux-gkeop-5.15, linux-hwe-5.15, linux-ibm, linux-ibm-5.15, linux-intel-iotg, linux-intel-iotg-5.15, linux-kvm, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-nvidia, linux-oracle, linux-oracle-5.15, linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-6725-2 linux-aws, linux-aws-5.15 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-6338-1 linux, linux-aws, linux-aws-6.2, linux-hwe-6.2, linux-kvm, linux-lowlatency, linux-lowlatency-hwe-6.2, linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Oct 23, 2026
- USN-6338-2 linux-gcp, linux-gcp-6.2, linux-ibm, linux-oracle, linux-starfive vulnerabilities Ubuntu Security Notices (USN) · Oct 23, 2026
- WID-SEC-2023-1255 Linux Kernel (ksmbd): Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 3, 2025