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Vulnerability · Published Apr 1, 2025 · Assigned by Linux

CVE-2025-21955ksmbd: prevent connection release during oplock break notification

High 8.8

In plain English

A high-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.8High
Exploit odds (30 days)0.5%top 56.8% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linuxno fix listedDEBIAN-CVE-2025-21955
Debian:13linux6.12.20-1DEBIAN-CVE-2025-21955
Debian:14linux6.12.20-1DEBIAN-CVE-2025-21955
Ubuntu:22.04:LTSlinuxno fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux6.8.0-84.84UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-awsno fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-aws6.8.0-1039.41UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1039.41~22.04.1UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-azureno fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-azure6.8.0-1038.44UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-azure-6.116.11.0-1018.18~24.04.1UBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-azure-6.116.11.0-1018.18~24.04.1USN-7628-1
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1036.42~22.04.1UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-azure-nvidia6.8.0-1025.27UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-gcpno fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-gcp6.8.0-1040.42UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-gcp-6.116.11.0-1016.16~24.04.1UBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-gcp-6.116.11.0-1016.16~24.04.1USN-7605-1
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1040.42~22.04.1UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-gke6.8.0-1036.40UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-gkeopno fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1023.25UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-hwe-6.116.11.0-28.28~24.04.1UBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-hwe-6.116.11.0-28.28~24.04.1USN-7605-1
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-85.85~22.04.1UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-ibmno fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-ibm6.8.0-1037.37UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1037.37~22.04.1UBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-intelno fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-intel-iotgno fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-kvmno fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-lowlatencyno fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-84.84.1UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.116.11.0-1015.16~24.04.2USN-7605-2
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.116.11.0-1015.16~24.04.2UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-84.84.1~22.04.1UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1039.42UBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-nvidia-6.116.11.0-1012.12UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1039.42~22.04.1UBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1039.42.1UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-nvidia-tegrano fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1010.10UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-nvidia-tegra-igxno fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-oem-6.116.11.0-1024.24USN-7606-1
Ubuntu:24.04:LTSlinux-oem-6.116.11.0-1024.24UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-oracleno fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-oracle6.8.0-1037.38UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1037.38~22.04.1UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-raspino fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-raspi6.8.0-1039.43UBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-84.84~22.04.1UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2025-21955
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1018.19UBUNTU-CVE-2025-21955
Ubuntu:22.04:LTSlinux-xilinx-zynqmpno fix listedUBUNTU-CVE-2025-21955

Affected products (as reported)

VendorProductVersions
Linux Linux 0626e6641f6b467447c81dd7678a69c66f7746cf – before 8e6508c7ecb1802909f294827eff38f301d0c9370626e6641f6b467447c81dd7678a69c66f7746cf – before 09aeab68033161cb54f194da93e51a11aee6144b0626e6641f6b467447c81dd7678a69c66f7746cf – before a4261bbc33fbf99b99c80aa3a2c50976118029800626e6641f6b467447c81dd7678a69c66f7746cf – before f17d1c63a76b0fe8e9c78023a86507a3a6d62cfa0626e6641f6b467447c81dd7678a69c66f7746cf – before 3aa660c059240e0c795217182cf7df32909dd917
Linux Linux 5.15

References