Improper access control in Linux kernel - CVE-2026-63830

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Main Vulnerability Database Vulnerabilities #VU138821

Improper access control in Linux kernel - CVE-2026-63830

Published: July 20, 2026


Vulnerability identifier: #VU138821
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-63830
CWE-ID: CWE-284
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to modify the page cache contents.

The vulnerability exists due to improper access control in the sk_msg scatter-gather handling logic when processing SK_MSG transformations and BPF message helpers. A local user can trigger scatterlist entry transfers, shifts, splits, or copies that desynchronize sg.copy state to modify the page cache contents.

Exploitation requires the ability to reach a later SK_MSG verdict that exposes sg_virt(sge) as writable BPF ctx->data.


Affected software

Linux kernel
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Workstation Extension 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Enterprise Live Patching
Legacy Module
Development Tools Module
Public Cloud Module
Basesystem Module
SUSE Real Time Module
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-realtime (Ubuntu package)
linux-azure-fde-5.15 (Ubuntu package)
linux-ibm-5.15 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-intel-iotg (Ubuntu package)
linux-nvidia-tegra-igx (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-gkeop (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-azure-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-aws-7.0 (Ubuntu package)
linux-nvidia-7.0 (Ubuntu package)
kernel-livepatch-SLE15-SP7-RT_Update_22-debugsource
kernel-livepatch-6_4_0-150700_7_81-rt-debuginfo
kernel-livepatch-6_4_0-150700_7_81-rt
kernel-livepatch-SLE15-SP7_Update_23-debugsource
kernel-livepatch-6_4_0-150700_53_87-default-debuginfo
kernel-livepatch-6_4_0-150700_53_87-default
kernel-rt-debugsource
kernel-source-rt
kernel-devel-rt
kernel-rt-devel
gfs2-kmp-rt
ocfs2-kmp-rt
dlm-kmp-rt-debuginfo
kernel-rt
cluster-md-kmp-rt
dlm-kmp-rt
kernel-rt-devel-debuginfo
kernel-syms-rt
gfs2-kmp-rt-debuginfo
cluster-md-kmp-rt-debuginfo
ocfs2-kmp-rt-debuginfo
kernel-rt-debuginfo
kernel-syms
kernel-obs-build-debugsource
kernel-obs-build
kernel-default-devel
cluster-md-kmp-default-debuginfo
gfs2-kmp-default
ocfs2-kmp-default-debuginfo
dlm-kmp-default-debuginfo
kernel-default-debugsource
cluster-md-kmp-default
kernel-default-debuginfo
dlm-kmp-default
ocfs2-kmp-default
kernel-64kb-debugsource
kernel-default-extra-debuginfo
kernel-default-extra
kernel-azure-devel
kernel-azure-debuginfo
kernel-azure-devel-debuginfo
kernel-azure-debugsource
kernel-azure
kernel-default-livepatch
kernel-default-livepatch-devel
reiserfs-kmp-default-debuginfo
reiserfs-kmp-default
kernel-source
kernel-docs
gfs2-kmp-default-debuginfo
kernel-64kb-debuginfo
kernel-64kb-devel-debuginfo
kernel-64kb-devel
kernel-64kb
kernel-zfcpdump-debuginfo
kernel-zfcpdump-debugsource
kernel-zfcpdump
kernel-macros
kernel-devel
kernel-default-devel-debuginfo
kernel-default
kernel-default-base
bpftool
kernel-extra-modules
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-headers
kernel-debugsource
kernel-debuginfo
bpftool-debuginfo
kernel

How to mitigate CVE-2026-63830

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-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-ibm-5.15 (Ubuntu package) - update to 5.15.0-1111.115~20.04.1
linux-nvidia (Ubuntu package) - addressed in versions 5.15.0-1112.113, 7.0.0-1018.18
linux-intel-iotg (Ubuntu package) - update to 5.15.0-1112.118
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-gkeop (Ubuntu package) - addressed in versions 5.15.0-1100.108, 6.8.0-1052.56
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-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1
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-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
kernel-livepatch-SLE15-SP7-RT_Update_22-debugsource - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_7_81-rt-debuginfo - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_7_81-rt - update to 1-150700.1.3.1
kernel-livepatch-SLE15-SP7_Update_23-debugsource - update to 1-150700.15.3.2
kernel-livepatch-6_4_0-150700_53_87-default-debuginfo - update to 1-150700.15.3.2
kernel-livepatch-6_4_0-150700_53_87-default - update to 1-150700.15.3.2
kernel-rt-debugsource - update to 6.4.0-150700.7.81.1
kernel-source-rt - update to 6.4.0-150700.7.81.1
kernel-devel-rt - update to 6.4.0-150700.7.81.1
kernel-rt-devel - update to 6.4.0-150700.7.81.1
gfs2-kmp-rt - update to 6.4.0-150700.7.81.1
ocfs2-kmp-rt - update to 6.4.0-150700.7.81.1
dlm-kmp-rt-debuginfo - update to 6.4.0-150700.7.81.1
kernel-rt - update to 6.4.0-150700.7.81.1
cluster-md-kmp-rt - update to 6.4.0-150700.7.81.1
dlm-kmp-rt - update to 6.4.0-150700.7.81.1
kernel-rt-devel-debuginfo - update to 6.4.0-150700.7.81.1
kernel-syms-rt - update to 6.4.0-150700.7.81.1
gfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.81.1
cluster-md-kmp-rt-debuginfo - update to 6.4.0-150700.7.81.1
ocfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.81.1
kernel-rt-debuginfo - update to 6.4.0-150700.7.81.1
kernel-syms - update to 6.4.0-150700.53.87.1
kernel-obs-build-debugsource - update to 6.4.0-150700.53.87.2
kernel-obs-build - update to 6.4.0-150700.53.87.2
kernel-default-devel - update to 6.4.0-150700.53.87.3
cluster-md-kmp-default-debuginfo - update to 6.4.0-150700.53.87.3
gfs2-kmp-default - update to 6.4.0-150700.53.87.3
ocfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.87.3
dlm-kmp-default-debuginfo - update to 6.4.0-150700.53.87.3
kernel-default-debugsource - update to 6.4.0-150700.53.87.3
cluster-md-kmp-default - update to 6.4.0-150700.53.87.3
kernel-default-debuginfo - update to 6.4.0-150700.53.87.3
dlm-kmp-default - update to 6.4.0-150700.53.87.3
ocfs2-kmp-default - update to 6.4.0-150700.53.87.3
kernel-64kb-debugsource - update to 6.4.0-150700.53.87.3
kernel-default-extra-debuginfo - update to 6.4.0-150700.53.87.3
kernel-default-extra - update to 6.4.0-150700.53.87.3
kernel-azure-devel - update to 6.4.0-150700.53.87.3
kernel-azure-debuginfo - update to 6.4.0-150700.53.87.3
kernel-azure-devel-debuginfo - update to 6.4.0-150700.53.87.3
kernel-azure-debugsource - update to 6.4.0-150700.53.87.3
kernel-azure - update to 6.4.0-150700.53.87.3
kernel-default-livepatch - update to 6.4.0-150700.53.87.3
kernel-default-livepatch-devel - update to 6.4.0-150700.53.87.3
reiserfs-kmp-default-debuginfo - update to 6.4.0-150700.53.87.3
reiserfs-kmp-default - update to 6.4.0-150700.53.87.3
kernel-source - update to 6.4.0-150700.53.87.3
kernel-docs - update to 6.4.0-150700.53.87.3
gfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.87.3
kernel-64kb-debuginfo - update to 6.4.0-150700.53.87.3
kernel-64kb-devel-debuginfo - update to 6.4.0-150700.53.87.3
kernel-64kb-devel - update to 6.4.0-150700.53.87.3
kernel-64kb - update to 6.4.0-150700.53.87.3
kernel-zfcpdump-debuginfo - update to 6.4.0-150700.53.87.3
kernel-zfcpdump-debugsource - update to 6.4.0-150700.53.87.3
kernel-zfcpdump - update to 6.4.0-150700.53.87.3
kernel-macros - update to 6.4.0-150700.53.87.3
kernel-devel - update to 6.4.0-150700.53.87.3
kernel-default-devel-debuginfo - update to 6.4.0-150700.53.87.3
kernel-default - update to 6.4.0-150700.53.87.3
kernel-default-base - update to 6.4.0-150700.53.87.3.150700.17.49.2
bpftool - update to 6.6.0-145.3.29.160
kernel-extra-modules - update to 6.6.0-145.3.29.160
python3-perf-debuginfo - update to 6.6.0-145.3.29.160
python3-perf - update to 6.6.0-145.3.29.160
perf-debuginfo - update to 6.6.0-145.3.29.160
perf - update to 6.6.0-145.3.29.160
kernel-tools-devel - update to 6.6.0-145.3.29.160
kernel-tools-debuginfo - update to 6.6.0-145.3.29.160
kernel-tools - update to 6.6.0-145.3.29.160
kernel-source - update to 6.6.0-145.3.29.160
kernel-headers - update to 6.6.0-145.3.29.160
kernel-devel - update to 6.6.0-145.3.29.160
kernel-debugsource - update to 6.6.0-145.3.29.160
kernel-debuginfo - update to 6.6.0-145.3.29.160
bpftool-debuginfo - update to 6.6.0-145.3.29.160
kernel - update to 6.6.0-145.3.29.160

External References

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