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Vulnerability · Published May 8, 2026 · Assigned by Linux

CVE-2026-43378smb: server: fix use-after-free in smb2_open()

Critical 9.8

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 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.3%top 76.2% 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: smb: server: fix use-after-free in smb2_open() The opinfo pointer obtained via rcu_dereference(fp->f_opinfo) is dereferenced after rcu_read_unlock(), creating a use-after-free window.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.170-1DEBIAN-CVE-2026-43378
Debian:13linux6.12.85-1DEBIAN-CVE-2026-43378
Debian:14linux6.19.10-1DEBIAN-CVE-2026-43378
Ubuntu:22.04:LTSlinux5.15.0-187.197USN-8631-1
Ubuntu:22.04:LTSlinux5.15.0-187.197UBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux6.8.0-134.134UBUNTU-CVE-2026-43378
Ubuntu:25.10linux6.17.0-40.40USN-8490-1
Ubuntu:25.10linux6.17.0-40.40UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-aws5.15.0-1113.120UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-aws5.15.0-1113.120USN-8631-1
Ubuntu:24.04:LTSlinux-aws6.8.0-1060.63UBUNTU-CVE-2026-43378
Ubuntu:25.10linux-aws6.17.0-1019.19UBUNTU-CVE-2026-43378
Ubuntu:25.10linux-aws6.17.0-1019.19USN-8490-1
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-aws-6.176.17.0-1019.19~24.04.1USN-8490-1
Ubuntu:24.04:LTSlinux-aws-6.176.17.0-1019.19~24.04.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1060.63~22.04.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-azure5.15.0-1118.127USN-8631-1
Ubuntu:22.04:LTSlinux-azure5.15.0-1118.127UBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-azure6.8.0-1063.71UBUNTU-CVE-2026-43378
Ubuntu:25.10linux-azureno fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-azure-6.176.17.0-1021.21~24.04.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1063.71~22.04.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1118.127USN-8631-1
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1118.127UBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1062.69UBUNTU-CVE-2026-43378
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1062.69~22.04.1UBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-gcp5.15.0-1114.124UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-gcp5.15.0-1114.124USN-8661-1
Ubuntu:24.04:LTSlinux-gcp6.8.0-1063.69UBUNTU-CVE-2026-43378
Ubuntu:25.10linux-gcp6.17.0-1020.22USN-8490-1
Ubuntu:25.10linux-gcp6.17.0-1020.22UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-gcp-6.176.17.0-1020.22~24.04.1USN-8490-1
Ubuntu:24.04:LTSlinux-gcp-6.176.17.0-1020.22~24.04.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1063.69~22.04.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-gke5.15.0-1110.116USN-8661-3
Ubuntu:22.04:LTSlinux-gke5.15.0-1110.116UBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-gke6.8.0-1058.64UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1096.104UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1096.104USN-8631-1
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1045.48UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-hwe-6.176.17.0-40.40~24.04.1USN-8545-1
Ubuntu:24.04:LTSlinux-hwe-6.176.17.0-40.40~24.04.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-136.136~22.04.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-ibm5.15.0-1107.111UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-ibm5.15.0-1107.111USN-8631-1
Ubuntu:24.04:LTSlinux-ibm6.8.0-1060.61UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1060.61~22.04.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1108.114UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1108.114USN-8631-1
Ubuntu:22.04:LTSlinux-kvm5.15.0-1105.110UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-kvm5.15.0-1105.110USN-8631-1
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-190.200UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-190.200USN-8661-2
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-134.134.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-134.134.1~22.04.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1108.109USN-8631-1
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1108.109UBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1058.61UBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-nvidia-6.176.17.0-1026.26UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1058.61~22.04.1UBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1058.61.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1065.67USN-8631-1
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1065.67UBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1029.30UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1054.54UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1054.54USN-8631-3
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-oem-6.176.17.0-1028.28USN-8491-1
Ubuntu:24.04:LTSlinux-oem-6.176.17.0-1028.28UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-oracle5.15.0-1110.116UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-oracle5.15.0-1110.116USN-8631-2
Ubuntu:24.04:LTSlinux-oracle6.8.0-1057.58UBUNTU-CVE-2026-43378
Ubuntu:25.10linux-oracle6.17.0-1018.18USN-8490-1
Ubuntu:25.10linux-oracle6.17.0-1018.18UBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-oracle-6.176.17.0-1018.18~24.04.1USN-8490-1
Ubuntu:24.04:LTSlinux-oracle-6.176.17.0-1018.18~24.04.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1057.58~22.04.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-raspi5.15.0-1108.111USN-8661-5
Ubuntu:22.04:LTSlinux-raspi5.15.0-1108.111UBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-raspi6.8.0-1060.64UBUNTU-CVE-2026-43378
Ubuntu:25.10linux-raspi6.17.0-1021.21UBUNTU-CVE-2026-43378
Ubuntu:25.10linux-raspi6.17.0-1021.21USN-8546-1
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-43378
Ubuntu:25.10linux-realtime6.17.0-1017.19UBUNTU-CVE-2026-43378
Ubuntu:25.10linux-realtime6.17.0-1017.19USN-8490-2
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-43378
Ubuntu:25.10linux-riscv6.17.0-40.40.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-134.134~22.04.1UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-vmware6.8.0-1008.8UBUNTU-CVE-2026-43378
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1032.33UBUNTU-CVE-2026-43378
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1076.80USN-8631-1
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1076.80UBUNTU-CVE-2026-43378

Affected products (as reported)

VendorProductVersions
Linux Linux e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 – before e1b21e6066615e7d3d3a7aa2677e415e563fd7cce2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 – before b720c84087cb547f23ce03eab93568c1769e4556e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 – before 54b48ae83de8bb06e65079d96368efe359d4909ce2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 – before 8f5b1a7cb009a93c48e9e334a2f59a660f9afc07e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 – before 190e5f808e8058640b408ccfed25440b441a718ae2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 – before 1e689a56173827669a35da7cb2a3c78ed5c53680
Linux Linux 5.15

References