Out-of-bounds read in Linux kernel - CVE-2026-64380

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Main Vulnerability Database Vulnerabilities #VU139584

Out-of-bounds read in Linux kernel - CVE-2026-64380

Published: July 27, 2026


Vulnerability identifier: #VU139584
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-64380
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to an out-of-bounds read in posix_info_sid_size() in the SMB client when parsing truncated POSIX SIDs. A remote attacker can send a specially crafted SMB response to cause a denial of service.


Affected software

Linux kernel
SUSE Linux Enterprise Server 12 SP5
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise High Performance Computing 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Micro
SUSE Linux Micro Extras
SUSE Linux Enterprise Live Patching
Ubuntu
openEuler
linux (Ubuntu package)
linux-kvm (Ubuntu package)
linux-gcp (Ubuntu package)
linux-aws (Ubuntu package)
linux-azure (Ubuntu package)
linux-oracle (Ubuntu package)
linux-lowlatency (Ubuntu package)
linux-gke (Ubuntu package)
linux-aws-5.15 (Ubuntu package)
linux-lowlatency-hwe-5.15 (Ubuntu package)
linux-hwe-5.15 (Ubuntu package)
linux-fips (Ubuntu package)
linux-azure-5.15 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-realtime (Ubuntu package)
linux-azure-fde-5.15 (Ubuntu package)
linux-intel-iotg (Ubuntu package)
linux-ibm-5.15 (Ubuntu package)
linux-gkeop (Ubuntu package)
linux-nvidia-tegra-igx (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-ibm (Ubuntu package)
linux-intel-iotg-5.15 (Ubuntu package)
linux-oracle-5.15 (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-xilinx-zynqmp (Ubuntu package)
linux-intel-iot-realtime (Ubuntu package)
linux-gcp-fips (Ubuntu package)
linux-aws-fips (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-raspi (Ubuntu package)
linux-nvidia-bos (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-aws-7.0 (Ubuntu package)
linux-nvidia-7.0 (Ubuntu package)
kgraft-patch-4_12_14-122_328-default
kernel-default-kgraft-devel
kernel-macros
kernel-devel
kernel-source
kernel-default-devel-debuginfo
kernel-default-base
kernel-default-devel
cluster-md-kmp-default
gfs2-kmp-default
ocfs2-kmp-default-debuginfo
kernel-default
kernel-default-debugsource
kernel-default-man
kernel-default-debuginfo
kernel-default-kgraft
kernel-syms
cluster-md-kmp-default-debuginfo
dlm-kmp-default-debuginfo
kernel-default-base-debuginfo
ocfs2-kmp-default
dlm-kmp-default
gfs2-kmp-default-debuginfo
python3-perf
bpftool
bpftool-debuginfo
kernel-debuginfo
kernel-debugsource
kernel-headers
kernel-tools
kernel-tools-debuginfo
kernel-tools-devel
perf
perf-debuginfo
python3-perf-debuginfo
kernel
kernel-64kb
kernel-64kb-debugsource
kernel-64kb-devel
kernel-obs-build
kernel-obs-build-debugsource
kernel-extra-modules

How to mitigate CVE-2026-64380

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 5.15.0-198.208, 6.8.0-147.147, 7.0.0-31.31
linux-kvm (Ubuntu package) - update to 5.15.0-1109.114
linux-gcp (Ubuntu package) - addressed in versions 5.15.0-1118.128, 6.8.0-1071.79, 7.0.0-1011.11
linux-aws (Ubuntu package) - addressed in versions 5.15.0-1117.124, 6.8.0-1067.70, 7.0.0-1012.12
linux-azure (Ubuntu package) - addressed in versions 5.15.0-1123.132, 6.8.0-1071.79, 7.0.0-1014.14
linux-oracle (Ubuntu package) - addressed in versions 5.15.0-1114.120, 6.8.0-1064.67, 7.0.0-1011.11
linux-lowlatency (Ubuntu package) - addressed in versions 5.15.0-195.205, 6.8.0-147.147.1
linux-gke (Ubuntu package) - addressed in versions 5.15.0-1113.119, 6.8.0-1066.74, 7.0.0-1006.7
linux-aws-5.15 (Ubuntu package) - update to 5.15.0-1117.124~20.04.1
linux-lowlatency-hwe-5.15 (Ubuntu package) - update to 5.15.0-195.205~20.04.1
linux-hwe-5.15 (Ubuntu package) - update to 5.15.0-198.208~20.04.1
linux-fips (Ubuntu package) - addressed in versions 5.15.0-198.208+fips1, 6.8.0-147.147+fips1
linux-azure-5.15 (Ubuntu package) - update to 5.15.0-1123.132~20.04.1
linux-nvidia (Ubuntu package) - addressed in versions 5.15.0-1112.113, 7.0.0-1018.18
linux-realtime (Ubuntu package) - addressed in versions 5.15.0-1116.125, 6.8.1-1062.63, 7.0.0-31.31.1
linux-azure-fde-5.15 (Ubuntu package) - update to 5.15.0-1122.131~20.04.1
linux-intel-iotg (Ubuntu package) - update to 5.15.0-1112.118
linux-ibm-5.15 (Ubuntu package) - update to 5.15.0-1111.115~20.04.1
linux-gkeop (Ubuntu package) - addressed in versions 5.15.0-1100.108, 6.8.0-1052.56
linux-nvidia-tegra-igx (Ubuntu package) - update to 5.15.0-1059.59
linux-nvidia-tegra (Ubuntu package) - addressed in versions 5.15.0-1070.72, 6.8.0-1036.39
linux-ibm (Ubuntu package) - addressed in versions 5.15.0-1111.115, 6.8.0-1067.68, 7.0.0-1013.13
linux-intel-iotg-5.15 (Ubuntu package) - update to 5.15.0-1112.118~20.04.1
linux-oracle-5.15 (Ubuntu package) - update to 5.15.0-1114.120~20.04.1
linux-gcp-5.15 (Ubuntu package) - update to 5.15.0-1118.128~20.04.1
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1070.72~20.04.1
linux-azure-fde (Ubuntu package) - addressed in versions 5.15.0-1122.131, 6.8.0-1069.76
linux-xilinx-zynqmp (Ubuntu package) - update to 5.15.0-1080.84
linux-intel-iot-realtime (Ubuntu package) - update to 5.15.0-1109.111
linux-gcp-fips (Ubuntu package) - addressed in versions 5.15.0-1118.128+fips1, 6.8.0-1071.79+fips1
linux-aws-fips (Ubuntu package) - addressed in versions 5.15.0-1117.124+fips1, 6.8.0-1067.70+fips1
linux-azure-fips (Ubuntu package) - addressed in versions 5.15.0-1123.132+fips1, 6.8.0-1071.79+fips1
linux-raspi (Ubuntu package) - update to 7.0.0-1019.19
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2018.18
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-31.31~24.04.1
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1013.13
linux-aws-7.0 (Ubuntu package) - update to 7.0.0-1012.12~24.04.1
linux-nvidia-7.0 (Ubuntu package) - update to 7.0.0-1018.18~24.04.1
kgraft-patch-4_12_14-122_328-default - update to 1-8.5.1
kernel-default-kgraft-devel - update to 4.12.14-122.328.1
kernel-macros - update to 4.12.14-122.328.1
kernel-devel - update to 4.12.14-122.328.1
kernel-source - update to 4.12.14-122.328.1
kernel-default-devel-debuginfo - addressed in versions 4.12.14-122.328.1, 6.4.0-159998.55.1
kernel-default-base - update to 4.12.14-122.328.1
kernel-default-devel - addressed in versions 4.12.14-122.328.1, 6.4.0-159998.55.1
cluster-md-kmp-default - update to 4.12.14-122.328.1
gfs2-kmp-default - update to 4.12.14-122.328.1
ocfs2-kmp-default-debuginfo - update to 4.12.14-122.328.1
kernel-default - addressed in versions 4.12.14-122.328.1, 6.4.0-159998.55.1
kernel-default-debugsource - addressed in versions 4.12.14-122.328.1, 6.4.0-159998.55.1
kernel-default-man - update to 4.12.14-122.328.1
kernel-default-debuginfo - update to 4.12.14-122.328.1
kernel-default-kgraft - update to 4.12.14-122.328.1
kernel-syms - addressed in versions 4.12.14-122.328.1, 6.4.0-159998.55.1
cluster-md-kmp-default-debuginfo - update to 4.12.14-122.328.1
dlm-kmp-default-debuginfo - update to 4.12.14-122.328.1
kernel-default-base-debuginfo - update to 4.12.14-122.328.1
ocfs2-kmp-default - update to 4.12.14-122.328.1
dlm-kmp-default - update to 4.12.14-122.328.1
gfs2-kmp-default-debuginfo - update to 4.12.14-122.328.1
python3-perf - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
bpftool - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
bpftool-debuginfo - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-debuginfo - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-debugsource - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-devel - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-headers - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-source - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-tools - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-tools-debuginfo - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-tools-devel - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
perf - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
perf-debuginfo - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
python3-perf-debuginfo - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel - addressed in versions 5.10.0-328.0.0.229, 6.6.0-145.3.29.160
kernel-64kb - update to 6.4.0-159998.55.1
kernel-64kb-debugsource - update to 6.4.0-159998.55.1
kernel-64kb-devel - update to 6.4.0-159998.55.1
kernel-obs-build - update to 6.4.0-159998.55.1
kernel-obs-build-debugsource - update to 6.4.0-159998.55.1
kernel-extra-modules - update to 6.6.0-145.3.29.160

External References

Related Security Bulletins