Out-of-bounds read in Linux kernel - CVE-2026-64191

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Main Vulnerability Database Vulnerabilities #VU138905

Out-of-bounds read in Linux kernel - CVE-2026-64191

Published: July 21, 2026


Vulnerability identifier: #VU138905
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-64191
CWE-ID: CWE-125
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to out-of-bounds read and out-of-bounds write in stub_xfer() in the i2c-stub driver when handling an I2C_SMBUS ioctl with I2C_SMBUS_I2C_BLOCK_DATA and an invalid block length. A local user can issue a crafted ioctl request with data->block[0] greater than 32 to cause a denial of service.

The issue affects the development and test i2c-stub driver, which is not built by default and must be loaded with a chip_addr= parameter.


Affected software

Linux kernel
SUSE Linux Enterprise Server 12 SP5
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise High Performance Computing 12
Red Hat CodeReady Linux Builder for x86_64
Red Hat CodeReady Linux Builder for ARM 64
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for Real Time for NFV
Red Hat Enterprise Linux for Real Time
Red Hat Enterprise Linux Server - AUS
Red Hat CodeReady Linux Builder for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support
Red Hat CodeReady Linux Builder for IBM z Systems - Extended Update Support
Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support
SUSE Linux Enterprise Live Patching
openEuler
Ubuntu
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
linux-nvidia-tegra-igx (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux (Ubuntu package)
linux-lowlatency (Ubuntu package)
linux-azure (Ubuntu package)
linux-gcp (Ubuntu package)
linux-aws (Ubuntu package)
linux-ibm (Ubuntu package)
linux-oracle (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-realtime (Ubuntu package)
linux-fips (Ubuntu package)
linux-gkeop (Ubuntu package)
linux-gke (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-aws-fips (Ubuntu package)
linux-gcp-fips (Ubuntu package)
kgraft-patch-4_12_14-122_333-default
kernel (Red Hat package)
kernel-rt (Red Hat package)
kernel-default-devel
kernel-default
kernel-default-kgraft
kernel-default-debugsource
kernel-default-kgraft-devel
kernel-default-debuginfo
dlm-kmp-default
dlm-kmp-default-debuginfo
ocfs2-kmp-default
cluster-md-kmp-default
kernel-default-base-debuginfo
kernel-syms
kernel-default-base
cluster-md-kmp-default-debuginfo
ocfs2-kmp-default-debuginfo
kernel-default-man
kernel-devel
kernel-source
kernel-macros
kernel-default-devel-debuginfo
gfs2-kmp-default
gfs2-kmp-default-debuginfo
python3-perf-debuginfo
kernel
bpftool
bpftool-debuginfo
kernel-debuginfo
kernel-debugsource
kernel-tools
kernel-tools-devel
kernel-tools-debuginfo
perf
perf-debuginfo
python2-perf
python2-perf-debuginfo
python3-perf
kernel-headers
kernel-extra-modules
linux-nvidia (Ubuntu package)
linux-oracle-5.15 (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)
linux-nvidia-7.0 (Ubuntu package)
linux-raspi (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

How to mitigate CVE-2026-64191

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
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, 6.8.0-1035.38
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1070.72~20.04.1
linux (Ubuntu package) - addressed in versions 5.15.0-195.205~20.04.1, 5.15.0-195.205, 5.15.0-198.208~20.04.1, 5.15.0-198.208+fips1, 5.15.0-1080.84, 5.15.0-1100.108, 5.15.0-1109.111, 5.15.0-1109.114, 5.15.0-1111.115~20.04.1, 5.15.0-1111.115, 5.15.0-1112.118~20.04.1, 5.15.0-1112.118, 5.15.0-1113.119, 5.15.0-1114.120, 5.15.0-1116.125~20.04.1, 5.15.0-1117.124~20.04.1, 5.15.0-1117.124, 5.15.0-1117.124+fips1, 5.15.0-1122.131~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1123.132, 5.15.0-1123.132+fips1, 5.15.0.195.160, 5.15.0.195.205~20.04.1, 5.15.0.198.114, 5.15.0.198.171, 5.15.0.198.208~20.04.1, 5.15.0.1080.83~20.04.1, 5.15.0.1100.99, 5.15.0.1109.105, 5.15.0.1109.113, 5.15.0.1111.108, 5.15.0.1111.115~20.04.1, 5.15.0.1112.111, 5.15.0.1112.118~20.04.1, 5.15.0.1113.112, 5.15.0.1114.110, 5.15.0.1116.120, 5.15.0.1117.113, 5.15.0.1117.120, 5.15.0.1117.124~20.04.1, 5.15.0.1122.131~20.04.1, 5.15.0.1123.107, 5.15.0.1123.121, 5.15.0.1123.132~20.04.1, 6.8.0-147.147, 7.0.0-31.31~24.04.1, 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12~24.04.1, 7.0.0-1012.12
linux-lowlatency (Ubuntu package) - update to 6.8.0-147.147.1
linux-azure (Ubuntu package) - addressed in versions 6.8.0-1071.79, 7.0.0-1011.11, 7.0.0-1014.14
linux-gcp (Ubuntu package) - addressed in versions 5.15.0-1118.128, 5.15.0-1118.128+fips1, 5.15.0.1118.107, 5.15.0.1118.115, 6.8.0-1071.79
linux-aws (Ubuntu package) - update to 6.8.0-1067.70
linux-ibm (Ubuntu package) - addressed in versions 6.8.0-1067.68, 7.0.0-1013.13
linux-oracle (Ubuntu package) - update to 6.8.0-1064.67
linux-azure-fde (Ubuntu package) - update to 6.8.0-1069.76
linux-realtime (Ubuntu package) - update to 6.8.1-1062.63
linux-fips (Ubuntu package) - update to 6.8.0-147.147+fips1
linux-gkeop (Ubuntu package) - update to 6.8.0-1052.56
linux-gke (Ubuntu package) - update to 6.8.0-1066.74
linux-azure-fips (Ubuntu package) - update to 6.8.0-1071.79+fips1
linux-aws-fips (Ubuntu package) - update to 6.8.0-1067.70+fips1
linux-gcp-fips (Ubuntu package) - update to 6.8.0-1071.79+fips1
kgraft-patch-4_12_14-122_333-default - update to 1-8.3.3
kernel (Red Hat package) - addressed in versions 3.10.0-1160.162.1.el7, 4.18.0-305.206.1.el8_4, 4.18.0-372.213.1.el8_6, 4.18.0-553.158.1.el8_10, 5.14.0-427.153.1.el9_4, 5.14.0-687.42.1.el9_8, 6.12.0-55.108.1.el10_0
kernel-rt (Red Hat package) - addressed in versions 3.10.0-1160.162.1.rt56.1314.el7, 4.18.0-553.158.1.rt7.499.el8_10, 5.14.0-284.195.1.rt14.480.el9_2
kernel-default-devel - update to 4.12.14-122.333.2
kernel-default - update to 4.12.14-122.333.2
kernel-default-kgraft - update to 4.12.14-122.333.2
kernel-default-debugsource - update to 4.12.14-122.333.2
kernel-default-kgraft-devel - update to 4.12.14-122.333.2
kernel-default-debuginfo - update to 4.12.14-122.333.2
dlm-kmp-default - update to 4.12.14-122.333.2
dlm-kmp-default-debuginfo - update to 4.12.14-122.333.2
ocfs2-kmp-default - update to 4.12.14-122.333.2
cluster-md-kmp-default - update to 4.12.14-122.333.2
kernel-default-base-debuginfo - update to 4.12.14-122.333.2
kernel-syms - update to 4.12.14-122.333.2
kernel-default-base - update to 4.12.14-122.333.2
cluster-md-kmp-default-debuginfo - update to 4.12.14-122.333.2
ocfs2-kmp-default-debuginfo - update to 4.12.14-122.333.2
kernel-default-man - update to 4.12.14-122.333.2
kernel-devel - update to 4.12.14-122.333.2
kernel-source - update to 4.12.14-122.333.2
kernel-macros - update to 4.12.14-122.333.2
kernel-default-devel-debuginfo - update to 4.12.14-122.333.2
gfs2-kmp-default - update to 4.12.14-122.333.2
gfs2-kmp-default-debuginfo - update to 4.12.14-122.333.2
python3-perf-debuginfo - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-327.0.0.228, 6.6.0-145.3.29.160
kernel - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-327.0.0.228, 6.6.0-145.3.29.160
bpftool - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-327.0.0.228, 6.6.0-145.3.29.160
bpftool-debuginfo - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-327.0.0.228, 6.6.0-145.3.29.160
kernel-debuginfo - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-327.0.0.228, 6.6.0-145.3.29.160
kernel-debugsource - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-327.0.0.228, 6.6.0-145.3.29.160
kernel-devel - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-327.0.0.228, 6.6.0-145.3.29.160
kernel-source - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-327.0.0.228, 6.6.0-145.3.29.160
kernel-tools - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-327.0.0.228, 6.6.0-145.3.29.160
kernel-tools-devel - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-327.0.0.228, 6.6.0-145.3.29.160
kernel-tools-debuginfo - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-327.0.0.228, 6.6.0-145.3.29.160
perf - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-327.0.0.228, 6.6.0-145.3.29.160
perf-debuginfo - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-327.0.0.228, 6.6.0-145.3.29.160
python2-perf - update to 4.19.90-2608.3.0.0385
python2-perf-debuginfo - update to 4.19.90-2608.3.0.0385
python3-perf - addressed in versions 4.19.90-2608.3.0.0385, 5.10.0-327.0.0.228, 6.6.0-145.3.29.160
kernel-headers - addressed in versions 5.10.0-327.0.0.228, 6.6.0-145.3.29.160
kernel-extra-modules - update to 6.6.0-145.3.29.160
linux-nvidia (Ubuntu package) - addressed in versions 5.15.0-1112.113, 5.15.0.1112.112, 7.0.0-1018.18
linux-oracle-5.15 (Ubuntu package) - addressed in versions 5.15.0-1114.120~20.04.1, 5.15.0.1114.120~20.04.1
linux-gcp-5.15 (Ubuntu package) - addressed in versions 5.15.0-1118.128~20.04.1, 5.15.0.1118.128~20.04.1
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-oem-7.0 (Ubuntu package) - update to 7.0.0-1013.13
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1
linux-nvidia-7.0 (Ubuntu package) - update to 7.0.0-1018.18~24.04.1
linux-raspi (Ubuntu package) - update to 7.0.0-1019.19
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2018.18

External References

Related Security Bulletins