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

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

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).

Linux kernel
openEuler
Ubuntu
bpftool
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-source
kernel-headers
kernel-devel
kernel-debugsource
kernel-debuginfo
bpftool-debuginfo
kernel
linux (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
bpftool - 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
perf - 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
kernel - update to 5.10.0-330.0.0.231
linux (Ubuntu package) - addressed in versions 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-31.31~24.04.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12, 7.0.0-1012.12~24.04.1
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

• https://git.kernel.org/stable/c/1697957eb0971d420dde42862b88eb43506a1105
• https://git.kernel.org/stable/c/47b5d3d506609b08b2e1f7c14f0b681a1953d572
• https://git.kernel.org/stable/c/8165f7ff57d9667d2bb477ef6af83ede7fed4ad7
• https://git.kernel.org/stable/c/9831bc9ecb402957810c2045c663fbfe9b09e296

• Improper access control in Linux kernel ipv4
• openEuler 22.03 LTS SP4 update for kernel
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux
• Ubuntu update for linux-gcp-7.0