Improper access control in Linux kernel - CVE-2026-63829

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Main Vulnerability Database Vulnerabilities #VU138820

Improper access control in Linux kernel - CVE-2026-63829

Published: July 20, 2026


Vulnerability identifier: #VU138820
CSH Severity: Low
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-63829
CWE-ID: CWE-284
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local privileged user to modify tunnel configuration across network namespaces.

The vulnerability exists due to improper access control in ipgre_changelink() and erspan_changelink() when handling RTM_NEWLINK changelink requests for GRE tunnel devices. A local privileged user can send a crafted RTM_NEWLINK request to modify tunnel configuration across network namespaces.

The issue occurs when the device network namespace differs from the tunnel link network namespace, because the check was performed only against dev_net(dev).


Affected software

Linux kernel
Red Hat CodeReady Linux Builder for ARM 64
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat CodeReady Linux Builder for x86_64
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
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-tegra (Ubuntu package)
linux-azure-fde-5.15 (Ubuntu package)
linux-realtime (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-intel-iotg (Ubuntu package)
linux-nvidia-tegra-igx (Ubuntu package)
linux-gkeop (Ubuntu package)
linux-ibm-5.15 (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-azure-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-aws-7.0 (Ubuntu package)
linux-nvidia-7.0 (Ubuntu package)
kernel (Red Hat package)
kernel-rt (Red Hat package)
perf
kernel
python3-perf-debuginfo
python3-perf
perf-debuginfo
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-source
kernel-headers
kernel-devel
kernel-debugsource
kernel-debuginfo
bpftool-debuginfo
bpftool

How to mitigate CVE-2026-63829

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-tegra (Ubuntu package) - addressed in versions 5.15.0-1070.72, 6.8.0-1035.38
linux-azure-fde-5.15 (Ubuntu package) - update to 5.15.0-1122.131~20.04.1
linux-realtime (Ubuntu package) - addressed in versions 5.15.0-1116.125, 6.8.1-1062.63, 7.0.0-31.31.1
linux-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-gkeop (Ubuntu package) - addressed in versions 5.15.0-1100.108, 6.8.0-1052.56
linux-ibm-5.15 (Ubuntu package) - update to 5.15.0-1111.115~20.04.1
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-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-gcp-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 (Red Hat package) - addressed in versions 4.18.0-553.171.1.el8_10, 5.14.0-687.55.1.el9_8
kernel-rt (Red Hat package) - update to 4.18.0-553.171.1.rt7.512.el8_10
perf - update to 5.10.0-330.0.0.231
kernel - update to 5.10.0-330.0.0.231
python3-perf-debuginfo - update to 5.10.0-330.0.0.231
python3-perf - update to 5.10.0-330.0.0.231
perf-debuginfo - update to 5.10.0-330.0.0.231
kernel-tools-devel - update to 5.10.0-330.0.0.231
kernel-tools-debuginfo - update to 5.10.0-330.0.0.231
kernel-tools - update to 5.10.0-330.0.0.231
kernel-source - update to 5.10.0-330.0.0.231
kernel-headers - update to 5.10.0-330.0.0.231
kernel-devel - update to 5.10.0-330.0.0.231
kernel-debugsource - update to 5.10.0-330.0.0.231
kernel-debuginfo - update to 5.10.0-330.0.0.231
bpftool-debuginfo - update to 5.10.0-330.0.0.231
bpftool - update to 5.10.0-330.0.0.231

External References

Related Security Bulletins