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Vulnerability · Published Oct 4, 2025 · Assigned by Linux

CVE-2025-39943ksmbd: smbdirect: validate data_offset and data_length field of smb_direct_data_transfer

Critical 9.4

In plain English

A critical-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 0.3% (higher than 18% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.4Critical
Exploit odds (30 days)0.3%top 81.6% 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: smbdirect: validate data_offset and data_length field of smb_direct_data_transfer If data_offset and data_length of smb_direct_data_transfer struct are invalid, out of bounds issue could happen. This patch validate data_offset and data_length field in recv_done.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.158-1DSA-6053-1
Debian:12linux6.1.158-1DEBIAN-CVE-2025-39943
Debian:13linux6.12.57-1DEBIAN-CVE-2025-39943
Debian:14linux6.16.9-1DEBIAN-CVE-2025-39943
Ubuntu:22.04:LTSlinux5.15.0-170.180UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux5.15.0-170.180USN-8033-1
Ubuntu:24.04:LTSlinux6.8.0-106.106UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-aws5.15.0-1100.107UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-aws5.15.0-1100.107USN-8033-1
Ubuntu:24.04:LTSlinux-aws6.8.0-1050.53UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1050.53~22.04.1UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-azure5.15.0-1109.118USN-8163-2
Ubuntu:22.04:LTSlinux-azure5.15.0-1109.118UBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-azure6.8.0-1051.57UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1051.57~22.04.1UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1109.118.1UBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1058.65UBUNTU-CVE-2025-39943
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1058.65~22.04.1UBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-gcp5.15.0-1100.109USN-8033-1
Ubuntu:22.04:LTSlinux-gcp5.15.0-1100.109UBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-gcp6.8.0-1052.55UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1052.55~22.04.1UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-gke5.15.0-1096.102UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-gke5.15.0-1096.102USN-8033-1
Ubuntu:24.04:LTSlinux-gke6.8.0-1048.53UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1083.91UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1083.91USN-8033-1
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1035.38UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-106.106~22.04.1UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-ibm5.15.0-1094.97USN-8033-1
Ubuntu:22.04:LTSlinux-ibm5.15.0-1094.97UBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-ibm6.8.0-1049.49UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1049.49~22.04.1UBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-intelno fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1095.101UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1095.101USN-8033-8
Ubuntu:22.04:LTSlinux-kvm5.15.0-1092.97UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-kvm5.15.0-1092.97USN-8033-5
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-170.180UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-170.180USN-8033-1
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-106.106.1UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-106.106.1~22.04.1UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1095.96UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1095.96USN-8033-6
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1049.52UBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1049.52~22.04.1UBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1049.52.1UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1052.52USN-8034-1
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1052.52UBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1020.20UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1041.41UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1041.41USN-8034-2
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-oracle5.15.0-1097.103USN-8033-5
Ubuntu:22.04:LTSlinux-oracle5.15.0-1097.103UBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-oracle6.8.0-1047.48UBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1047.48~22.04.1UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-raspi5.15.0-1097.100UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-raspi5.15.0-1097.100USN-8141-1
Ubuntu:24.04:LTSlinux-raspi6.8.0-1050.54UBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-106.106~22.04.1UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2025-39943
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1028.29UBUNTU-CVE-2025-39943
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1064.68USN-8033-7
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1064.68UBUNTU-CVE-2025-39943

Affected products (as reported)

VendorProductVersions
Linux Linux 2ea086e35c3d726a3bacd0a971c1f02a50e98206 – before 773fddf976d282ef059c36c575ddb81567acd6bc2ea086e35c3d726a3bacd0a971c1f02a50e98206 – before bdaab5c6538e250a9654127e688ecbbeb6f771d52ea086e35c3d726a3bacd0a971c1f02a50e98206 – before eb0378dde086363046ed3d7db7f126fc3f76fd702ea086e35c3d726a3bacd0a971c1f02a50e98206 – before 8be498fcbd5b07272f560b45981d4b9e5a2ad8852ea086e35c3d726a3bacd0a971c1f02a50e98206 – before 529b121b00a6ee3c88fb3c01b443b2b81f686d482ea086e35c3d726a3bacd0a971c1f02a50e98206 – before 5282491fc49d5614ac6ddcd012e5743eecb6a67c
Linux Linux 5.15

References