Description
A flaw was found in the Linux kernel's ksmbd, a high-performance in-kernel SMB server. The specific flaw exists within the handling of SMB2_SESSION_SETUP commands. The issue results from the lack of control of resource consumption. An attacker can leverage this vulnerability to create a denial-of-service condition on the system.
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 | 5.15.0-1038.40 | — |
| Ubuntu 24.04 LTS | linux-raspi-realtime | No fix yet | — |
| Ubuntu 22.04 LTS | linux +1 | 5.15.0-101.111 | USN-6704-1 |
| Ubuntu 22.04 LTS | linux-aws | 5.15.0-1056.61 | USN-6705-1 |
| 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 | 5.15.0-1059.67 | USN-6704-1 |
| Ubuntu 22.04 LTS | linux-azure-fde | 5.15.0-1059.67.1 | USN-6704-1 |
| Ubuntu 22.04 LTS | linux-gcp | 5.15.0-1054.62 | USN-6704-1 |
| 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 | 5.15.0-1053.58 | USN-6704-1 |
| Ubuntu 22.04 LTS | linux-gkeop | 5.15.0-1039.45 | USN-6704-1 |
| 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 | 5.15.0-1049.52 | USN-6704-2, USN-6704-1 |
| Ubuntu 22.04 LTS | linux-intel-iotg | 5.15.0-1051.57 | USN-6704-4 |
| 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 | 5.15.0-1047.47 | USN-6704-1 |
| 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 | 5.15.0-1054.60 | USN-6704-3 |
| 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 | 5.15.0-1056.61~20.04.1 | USN-6705-1 |
| Ubuntu 20.04 LTS | linux-azure-5.15 | 5.15.0-1059.67~20.04.1 | USN-6704-1 |
| Ubuntu 20.04 LTS | linux-azure-fde-5.15 | 5.15.0-1059.67~20.04.1.1 | USN-6704-1 |
| Ubuntu 20.04 LTS | linux-gcp-5.15 | 5.15.0-1054.62~20.04.1 | USN-6704-1 |
| Ubuntu 20.04 LTS | linux-gke +25 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-gkeop-5.15 | 5.15.0-1039.45~20.04.1 | USN-6704-1 |
| Ubuntu 20.04 LTS | linux-hwe-5.15 +1 | 5.15.0-101.111~20.04.1 | USN-6704-1 |
| Ubuntu 20.04 LTS | linux-ibm-5.15 | 5.15.0-1049.52~20.04.1 | USN-6704-1 |
| Ubuntu 20.04 LTS | linux-intel-iotg-5.15 | 5.15.0-1051.57~20.04.1 | USN-6704-4 |
| 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 | 5.15.0-1054.60~20.04.1 | USN-6704-3 |
| Ubuntu 20.04 LTS | linux-riscv-5.15 | 5.15.0-1052.56~20.04.1 | — |
| 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 | 5.15.0-1049.51 | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime | 5.15.0-1057.64 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-aws-fips | 5.15.0-1056.61+fips1 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-azure-fips | 5.15.0-1059.67+fips1 | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-fips | 5.15.0-101.111+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 | 5.15.126.1-1 | — |
Advisories 8
- 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
- USN-6704-1 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-kvm, linux-lowlatency, linux-lowlatency-hwe-5.15, linux-nvidia vulnerabilities Ubuntu Security Notices (USN) · Oct 22, 2026
- USN-6704-2 linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Oct 22, 2026
- USN-6705-1 linux-aws, linux-aws-5.15 vulnerabilities Ubuntu Security Notices (USN) · Oct 22, 2026
- USN-6704-3 linux-oracle, linux-oracle-5.15 vulnerabilities Ubuntu Security Notices (USN) · Oct 22, 2026
- USN-6704-4 linux-intel-iotg, linux-intel-iotg-5.15 vulnerabilities Ubuntu Security Notices (USN) · Oct 22, 2026
- WID-SEC-2023-1255 Linux Kernel (ksmbd): Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 3, 2025