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Vulnerability · Published Jul 25, 2026 · Assigned by Linux

CVE-2026-64380smb: client: harden POSIX SID length parsing

High 8.2

In plain English

A high-severity out-of-bounds read 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 0.4% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.2High
Exploit odds (30 days)0.4%top 61.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: smb: client: harden POSIX SID length parsing posix_info_sid_size() reads sid[1] to obtain the subauthority count, but its existing boundary check still accepts buffers with only one remaining byte. Require two bytes before reading sid[1] so all client paths that reuse the helper reject truncated POSIX SIDs safely.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.180-1DEBIAN-CVE-2026-64380
Debian:13linux6.12.96-1DEBIAN-CVE-2026-64380
Debian:14linux7.1.4-1DEBIAN-CVE-2026-64380
Debian:12linux-6.126.12.100-1~deb12u1DEBIAN-CVE-2026-64380
Ubuntu:22.04:LTSlinux5.15.0-198.208UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux6.8.0-147.147UBUNTU-CVE-2026-64380
Ubuntu:26.04:LTSlinux7.0.0-31.31UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-aws5.15.0-1117.124UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-aws6.8.0-1067.70UBUNTU-CVE-2026-64380
Ubuntu:26.04:LTSlinux-aws7.0.0-1012.12UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-aws-6.8no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-aws-7.07.0.0-1012.12~24.04.1UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-azure5.15.0-1123.132UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-azure6.8.0-1071.79UBUNTU-CVE-2026-64380
Ubuntu:26.04:LTSlinux-azure7.0.0-1014.14UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-azure-6.8no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-azure-7.07.0.0-1014.14~24.04.1UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1122.131UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1069.76UBUNTU-CVE-2026-64380
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1013.13UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-azure-fde-6.8no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-azure-fde-7.07.0.0-1013.13~24.04.1UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-gcp5.15.0-1118.128UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-gcp6.8.0-1071.79UBUNTU-CVE-2026-64380
Ubuntu:26.04:LTSlinux-gcp7.0.0-1011.11UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-gcp-6.8no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-gcp-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-gke5.15.0-1113.119UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-gke6.8.0-1066.74UBUNTU-CVE-2026-64380
Ubuntu:26.04:LTSlinux-gke7.0.0-1006.7UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1100.108UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1052.56UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-hwe-6.8no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-31.31~24.04.1UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-ibm5.15.0-1111.115UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-ibm6.8.0-1067.68UBUNTU-CVE-2026-64380
Ubuntu:26.04:LTSlinux-ibm7.0.0-1013.13UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-ibm-6.8no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1112.118UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-kvm5.15.0-1109.114UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-195.205UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-147.147.1UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.8no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1112.113UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-64380
Ubuntu:26.04:LTSlinux-nvidia7.0.0-1018.18UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-nvidia-6.8no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-nvidia-7.07.0.0-1018.18~24.04.1UBUNTU-CVE-2026-64380
Ubuntu:26.04:LTSlinux-nvidia-bos7.0.0-2018.18UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-nvidia-lowlatencyno fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1070.72UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1036.39UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1059.59UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-64380
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1013.13UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-oracle5.15.0-1114.120UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-oracle6.8.0-1064.67UBUNTU-CVE-2026-64380
Ubuntu:26.04:LTSlinux-oracle7.0.0-1011.11UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-oracle-6.8no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-oracle-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-64380
Ubuntu:26.04:LTSlinux-raspi7.0.0-1019.19UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-64380
Ubuntu:26.04:LTSlinux-realtime7.0.0-31.31.1UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-64380
Ubuntu:26.04:LTSlinux-riscv7.0.0-31.31.1UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-riscv-6.8no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-riscv-7.07.0.0-31.31.1~24.04.1UBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-vmware6.8.0-1008.8UBUNTU-CVE-2026-64380
Ubuntu:24.04:LTSlinux-xilinxno fix listedUBUNTU-CVE-2026-64380
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1080.84UBUNTU-CVE-2026-64380

Affected products (as reported)

VendorProductVersions
Linux Linux 349e13ad30b45998bb9937cfe0b32be6f951976d – before 171605aed68380c2fa75dff9b3a1ed427c50065b349e13ad30b45998bb9937cfe0b32be6f951976d – before 4213c1208978483021d7d125c131de3985d38f61349e13ad30b45998bb9937cfe0b32be6f951976d – before 96e889bc1e759c83f25093e8c2f3da31b4973f30349e13ad30b45998bb9937cfe0b32be6f951976d – before 0de5b8e76847f5de26f364a82c6602c4881c30da349e13ad30b45998bb9937cfe0b32be6f951976d – before 427eb7eb46425fec845a43e861f3d6e2899cae59349e13ad30b45998bb9937cfe0b32be6f951976d – before 86c5d470f5d42e61123b2f4b4f0b91f4eee5b980349e13ad30b45998bb9937cfe0b32be6f951976d – before 46a84715a015cb48e1b9c219dc88c03d8a541ea4349e13ad30b45998bb9937cfe0b32be6f951976d – before 7ad2bcf2441430bb2e918fb3ef9a90d775a6e422
Linux Linux 5.7

Weakness: CWE-125 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

References