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OpenAdvisories
High · 8.8 CVE-2025-21955 EUVD-2025-9365GHSA-p2c4-6w6j-w378

ksmbd: prevent connection release during oplock break notification

Published Apr 1, 2025 · Updated Oct 30, 2026 · Assigned by Linux

Vendor: Linux Product: Linux Package: linux Package: linux Package: linux-allwinner-5.19 Package: linux-aws Package: linux-aws-5.0 Package: linux-aws-5.11 Package: linux-aws-5.13 Package: linux-aws-5.15 Package: linux-aws-5.19 Package: linux-aws-5.3 Package: linux-aws-5.8 Package: linux-aws-6.2 Package: linux-aws-6.5 Package: linux-aws-6.8 Package: linux-aws-fips Package: linux-azure Package: linux-azure-5.11 Package: linux-azure-5.13 Package: linux-azure-5.15 Package: linux-azure-5.19 Package: linux-azure-5.3 Package: linux-azure-5.8 Package: linux-azure-6.11 Package: linux-azure-6.2 Package: linux-azure-6.5 Package: linux-azure-6.8 Package: linux-azure-edge Package: linux-azure-fde Package: linux-azure-fde-5.15 Package: linux-azure-fde-5.19 Package: linux-azure-fde-6.2 Package: linux-azure-fips Package: linux-azure-nvidia Package: linux-bluefield Package: linux-fips Package: linux-gcp Package: linux-gcp-5.11 Package: linux-gcp-5.13 Package: linux-gcp-5.15 Package: linux-gcp-5.19 Package: linux-gcp-5.3 Package: linux-gcp-5.8 Package: linux-gcp-6.11 Package: linux-gcp-6.2 Package: linux-gcp-6.5 Package: linux-gcp-6.8 Package: linux-gcp-fips Package: linux-gke Package: linux-gke-4.15 Package: linux-gke-5.15 Package: linux-gke-5.4 Package: linux-gkeop Package: linux-gkeop-5.15 Package: linux-gkeop-5.4 Package: linux-hwe Package: linux-hwe-5.11 Package: linux-hwe-5.13 Package: linux-hwe-5.15 Package: linux-hwe-5.19 Package: linux-hwe-5.8 Package: linux-hwe-6.11 Package: linux-hwe-6.2 Package: linux-hwe-6.5 Package: linux-hwe-6.8 Package: linux-hwe-edge Package: linux-ibm Package: linux-ibm-5.15 Package: linux-ibm-6.8 Package: linux-intel Package: linux-intel-5.13 Package: linux-intel-iot-realtime Package: linux-intel-iotg Package: linux-intel-iotg-5.15 Package: linux-kvm Package: linux-lowlatency Package: linux-lowlatency-hwe-5.15 Package: linux-lowlatency-hwe-5.19 Package: linux-lowlatency-hwe-6.11 Package: linux-lowlatency-hwe-6.2 Package: linux-lowlatency-hwe-6.5 Package: linux-lowlatency-hwe-6.8 Package: linux-nvidia Package: linux-nvidia-6.11 Package: linux-nvidia-6.2 Package: linux-nvidia-6.5 Package: linux-nvidia-6.8 Package: linux-nvidia-lowlatency Package: linux-nvidia-tegra Package: linux-nvidia-tegra-5.15 Package: linux-nvidia-tegra-igx Package: linux-oem Package: linux-oem-5.10 Package: linux-oem-5.13 Package: linux-oem-5.14 Package: linux-oem-5.17 Package: linux-oem-5.6 Package: linux-oem-6.0 Package: linux-oem-6.1 Package: linux-oem-6.11 Package: linux-oem-6.5 Package: linux-oem-6.8 Package: linux-oracle Package: linux-oracle-5.0 Package: linux-oracle-5.11 Package: linux-oracle-5.13 Package: linux-oracle-5.15 Package: linux-oracle-5.3 Package: linux-oracle-5.8 Package: linux-oracle-6.5 Package: linux-oracle-6.8 Package: linux-raspi Package: linux-raspi-realtime Package: linux-raspi2 Package: linux-realtime Package: linux-realtime-6.8 Package: linux-riscv Package: linux-riscv-5.11 Package: linux-riscv-5.15 Package: linux-riscv-5.19 Package: linux-riscv-5.8 Package: linux-riscv-6.5 Package: linux-riscv-6.8 Package: linux-starfive-5.19 Package: linux-starfive-6.2 Package: linux-starfive-6.5 Package: linux-vmware Package: linux-xilinx Package: linux-xilinx-zynqmp Platform: Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

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

ksmbd: prevent connection release during oplock break notification

ksmbd_work could be freed when after connection release.
Increment r_count of ksmbd_conn to indicate that requests
are not finished yet and to not release the connection.

Affected products

VendorProductAffectedFixed
Linux Linux 5.15 6.1.191

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 ↗
ReleasePackageFixed inAdvisory
Debian 14 linux 6.12.20-1 —
Debian 13 linux 6.12.20-1 —
Debian 12 linux No fix yet —

Ubuntu

Security tracker ↗
ReleasePackageFixed inAdvisory
Ubuntu Nvidia-BlueField 22.04 LTS linux-bluefield No fix yet —
Ubuntu 24.04 LTS linux 6.8.0-84.84 USN-7764-1
Ubuntu 24.04 LTS linux-aws 6.8.0-1039.41 USN-7764-1
Ubuntu 24.04 LTS linux-azure 6.8.0-1038.44 USN-7802-1
Ubuntu 24.04 LTS linux-azure-6.11 6.11.0-1018.18~24.04.1 USN-7628-1
Ubuntu 24.04 LTS linux-azure-nvidia 6.8.0-1025.27 USN-7809-1
Ubuntu 24.04 LTS linux-gcp 6.8.0-1040.42 USN-7764-1
Ubuntu 24.04 LTS linux-gcp-6.11 6.11.0-1016.16~24.04.1 USN-7605-1
Ubuntu 24.04 LTS linux-gke 6.8.0-1036.40 USN-7764-1
Ubuntu 24.04 LTS linux-gkeop 6.8.0-1023.25 USN-7764-1
Ubuntu 24.04 LTS linux-hwe-6.11 6.11.0-28.28~24.04.1 USN-7605-1
Ubuntu 24.04 LTS linux-ibm 6.8.0-1037.37 USN-7779-1
Ubuntu 24.04 LTS linux-intel +4 No fix yet —
Ubuntu 24.04 LTS linux-lowlatency 6.8.0-84.84.1 USN-7764-1
Ubuntu 24.04 LTS linux-lowlatency-hwe-6.11 6.11.0-1015.16~24.04.2 USN-7605-2
Ubuntu 24.04 LTS linux-nvidia 6.8.0-1039.42 USN-7765-1
Ubuntu 24.04 LTS linux-nvidia-6.11 6.11.0-1012.12 —
Ubuntu 24.04 LTS linux-nvidia-lowlatency 6.8.0-1039.42.1 USN-7765-1
Ubuntu 24.04 LTS linux-nvidia-tegra 6.8.0-1010.10 —
Ubuntu 24.04 LTS linux-oem-6.11 6.11.0-1024.24 USN-7606-1
Ubuntu 24.04 LTS linux-oracle 6.8.0-1037.38 USN-7801-2
Ubuntu 24.04 LTS linux-raspi 6.8.0-1039.43 USN-7790-1
Ubuntu 24.04 LTS linux-xilinx 6.8.0-1018.19 —
Ubuntu 22.04 LTS linux +49 No fix yet —
Ubuntu 22.04 LTS linux-aws-6.8 6.8.0-1039.41~22.04.1 USN-7766-1
Ubuntu 22.04 LTS linux-azure-6.8 6.8.0-1036.42~22.04.1 USN-7802-1
Ubuntu 22.04 LTS linux-gcp-6.8 6.8.0-1040.42~22.04.1 USN-7766-1
Ubuntu 22.04 LTS linux-hwe-6.8 6.8.0-85.85~22.04.1 USN-7801-1, USN-7764-2
Ubuntu 22.04 LTS linux-ibm-6.8 6.8.0-1037.37~22.04.1 USN-7779-1
Ubuntu 22.04 LTS linux-lowlatency-hwe-6.8 6.8.0-84.84.1~22.04.1 USN-7764-1
Ubuntu 22.04 LTS linux-nvidia-6.8 6.8.0-1039.42~22.04.1 USN-7765-1
Ubuntu 22.04 LTS linux-oracle-6.8 6.8.0-1037.38~22.04.1 USN-7801-3
Ubuntu 22.04 LTS linux-riscv-6.8 6.8.0-84.84~22.04.1 —
Ubuntu 20.04 LTS linux-gke +28 No fix yet —
Ubuntu 18.04 LTS linux-gcp +14 No fix yet —
Show 7 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 16.04 LTS linux-hwe-edge No fix yet —
Ubuntu Pro Realtime 24.04 LTS linux-raspi-realtime 6.8.0-2030.31 USN-7800-1
Ubuntu Pro Realtime 24.04 LTS linux-realtime 6.8.1-1034.35 USN-7767-1
Ubuntu Pro Realtime 22.04 LTS linux-realtime +1 No fix yet —
Ubuntu Pro Realtime 22.04 LTS linux-realtime-6.8 6.8.1-1034.35~22.04.1 USN-7767-2
Ubuntu Pro FIPS-updates 24.04 LTS linux-aws-fips 6.8.0-1039.41+fips1 —
Ubuntu Pro FIPS-updates 24.04 LTS linux-azure-fips 6.8.0-1040.46+fips1 —
Ubuntu Pro FIPS-updates 24.04 LTS linux-fips 6.8.0-84.84+fips1 —
Ubuntu Pro FIPS-updates 24.04 LTS linux-gcp-fips 6.8.0-1040.42+fips1 —
Ubuntu Pro FIPS-updates 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro FIPS-preview 22.04 LTS linux-fips +3 No fix yet —
Ubuntu Pro 20.04 LTS linux-aws-5.15 +10 No fix yet —

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 9 kernel-uek +34 6.12.0-101.33.4.3.el10uek ELSA-2025-20530, ELSA-2025-20480

Advisories 21

References