Integer underflow in Linux kernel - CVE-2026-63868

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Main Vulnerability Database Vulnerabilities #VU138790

Integer underflow in Linux kernel - CVE-2026-63868

Published: July 20, 2026


Vulnerability identifier: #VU138790
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-2026-63868
CWE-ID: CWE-191
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 unsigned integer underflow in garp_pdu_parse_attr in the GARP receive-side attribute parser when parsing crafted GARP attributes. A remote attacker can send crafted Join or Leave events to cause a denial of service.

The issue can cause received GARP events for common attributes, such as GVRP VLAN registration attributes, to be ignored.


Affected software

Linux kernel
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise Server 12 SP5
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise High Performance Computing 12
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Workstation Extension 15
SUSE Linux Micro
SUSE Linux Micro Extras
SUSE Linux Enterprise Live Patching
SUSE Real Time Module
Public Cloud Module
Legacy Module
Development Tools Module
Basesystem Module
Ubuntu
linux-nvidia-tegra-igx (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-realtime (Ubuntu package)
linux-fips (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-ibm-6.8 (Ubuntu package)
linux-gcp-6.8 (Ubuntu package)
linux-aws-fips (Ubuntu package)
linux-gcp-fips (Ubuntu package)
linux-realtime-6.8 (Ubuntu package)
kgraft-patch-4_12_14-122_328-default
kernel-livepatch-SLE15-SP7-RT_Update_20-debugsource
kernel-livepatch-6_4_0-150700_7_75-rt
kernel-livepatch-6_4_0-150700_7_75-rt-debuginfo
kernel-livepatch-SLE15-SP7_Update_21-debugsource
kernel-livepatch-6_4_0-150700_53_81-default-debuginfo
kernel-livepatch-6_4_0-150700_53_81-default
dlm-kmp-default-debuginfo
kernel-source
cluster-md-kmp-default-debuginfo
kernel-syms
kernel-default-kgraft
kernel-default-debuginfo
kernel-default-man
kernel-macros
kernel-devel
kernel-default
kernel-default-debugsource
kernel-default-kgraft-devel
ocfs2-kmp-default
kernel-default-devel-debuginfo
kernel-default-base
kernel-default-devel
cluster-md-kmp-default
gfs2-kmp-default
ocfs2-kmp-default-debuginfo
kernel-default-base-debuginfo
dlm-kmp-default
gfs2-kmp-default-debuginfo
kernel-64kb-debugsource
kernel-source-rt
kernel-rt-livepatch
kernel-rt-debugsource
kernel-rt-debuginfo
kernel-kvmsmall
kernel-default-livepatch
kernel-rt
kernel-devel-rt
kernel-kvmsmall-debugsource
kernel-64kb
kernel-kvmsmall-debuginfo
kernel-obs-build-debugsource
kernel-obs-build
kernel-64kb-devel
cluster-md-kmp-rt
dlm-kmp-rt
gfs2-kmp-rt-debuginfo
ocfs2-kmp-rt
kernel-rt-devel-debuginfo
kernel-syms-rt
ocfs2-kmp-rt-debuginfo
gfs2-kmp-rt
dlm-kmp-rt-debuginfo
cluster-md-kmp-rt-debuginfo
kernel-rt-devel
kernel-zfcpdump-debuginfo
kernel-zfcpdump-debugsource
kernel-zfcpdump
kernel-default-extra-debuginfo
kernel-default-extra
kernel-azure-devel-debuginfo
kernel-azure-debuginfo
kernel-azure-debugsource
kernel-azure-devel
kernel-azure
kernel-default-livepatch-devel
reiserfs-kmp-default-debuginfo
reiserfs-kmp-default
kernel-docs
kernel-64kb-devel-debuginfo
kernel-64kb-debuginfo
linux-nvidia (Ubuntu package)
linux-oracle-5.15 (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-gcp (Ubuntu package)
linux-gke (Ubuntu package)
linux-azure (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-ibm (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-2026-63868

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) - update to 5.15.0-1070.72
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, 6.8.0-146.146, 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-aws (Ubuntu package) - update to 6.8.0-1066.69
linux-realtime (Ubuntu package) - update to 6.8.1-1061.62
linux-fips (Ubuntu package) - update to 6.8.0-146.146+fips1
linux-aws-6.8 (Ubuntu package) - update to 6.8.0-1066.69~22.04.1
linux-ibm-6.8 (Ubuntu package) - update to 6.8.0-1066.67~22.04.1
linux-gcp-6.8 (Ubuntu package) - update to 6.8.0-1070.78~22.04.1
linux-aws-fips (Ubuntu package) - update to 6.8.0-1066.69+fips1
linux-gcp-fips (Ubuntu package) - update to 6.8.0-1070.78+fips1
linux-realtime-6.8 (Ubuntu package) - update to 6.8.1-1061.62~22.04.1
kgraft-patch-4_12_14-122_328-default - update to 1-8.5.1
kernel-livepatch-SLE15-SP7-RT_Update_20-debugsource - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_7_75-rt - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_7_75-rt-debuginfo - update to 1-150700.1.3.1
kernel-livepatch-SLE15-SP7_Update_21-debugsource - update to 1-150700.15.3.1
kernel-livepatch-6_4_0-150700_53_81-default-debuginfo - update to 1-150700.15.3.1
kernel-livepatch-6_4_0-150700_53_81-default - update to 1-150700.15.3.1
dlm-kmp-default-debuginfo - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
kernel-source - addressed in versions 4.12.14-122.328.1, 6.4.0-52.1, 6.4.0-150700.53.81.1
cluster-md-kmp-default-debuginfo - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
kernel-syms - addressed in versions 4.12.14-122.328.1, 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-kgraft - update to 4.12.14-122.328.1
kernel-default-debuginfo - addressed in versions 4.12.14-122.328.1, 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-man - update to 4.12.14-122.328.1
kernel-macros - addressed in versions 4.12.14-122.328.1, 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-devel - addressed in versions 4.12.14-122.328.1, 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default - addressed in versions 4.12.14-122.328.1, 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-debugsource - addressed in versions 4.12.14-122.328.1, 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-kgraft-devel - update to 4.12.14-122.328.1
ocfs2-kmp-default - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
kernel-default-devel-debuginfo - addressed in versions 4.12.14-122.328.1, 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-base - addressed in versions 4.12.14-122.328.1, 6.4.0-52.1.21.35, 6.4.0-52.1.21.36, 6.4.0-150700.53.81.1.150700.17.45.1
kernel-default-devel - addressed in versions 4.12.14-122.328.1, 6.4.0-52.1, 6.4.0-150700.53.81.1
cluster-md-kmp-default - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
gfs2-kmp-default - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
ocfs2-kmp-default-debuginfo - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
kernel-default-base-debuginfo - update to 4.12.14-122.328.1
dlm-kmp-default - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
gfs2-kmp-default-debuginfo - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
kernel-64kb-debugsource - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-source-rt - addressed in versions 6.4.0-52.1, 6.4.0-150700.7.75.1
kernel-rt-livepatch - update to 6.4.0-52.1
kernel-rt-debugsource - addressed in versions 6.4.0-52.1, 6.4.0-150700.7.75.1
kernel-rt-debuginfo - addressed in versions 6.4.0-52.1, 6.4.0-150700.7.75.1
kernel-kvmsmall - update to 6.4.0-52.1
kernel-default-livepatch - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-rt - addressed in versions 6.4.0-52.1, 6.4.0-150700.7.75.1
kernel-devel-rt - addressed in versions 6.4.0-52.1, 6.4.0-150700.7.75.1
kernel-kvmsmall-debugsource - update to 6.4.0-52.1
kernel-64kb - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-kvmsmall-debuginfo - update to 6.4.0-52.1
kernel-obs-build-debugsource - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-obs-build - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-64kb-devel - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
cluster-md-kmp-rt - update to 6.4.0-150700.7.75.1
dlm-kmp-rt - update to 6.4.0-150700.7.75.1
gfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.75.1
ocfs2-kmp-rt - update to 6.4.0-150700.7.75.1
kernel-rt-devel-debuginfo - update to 6.4.0-150700.7.75.1
kernel-syms-rt - update to 6.4.0-150700.7.75.1
ocfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.75.1
gfs2-kmp-rt - update to 6.4.0-150700.7.75.1
dlm-kmp-rt-debuginfo - update to 6.4.0-150700.7.75.1
cluster-md-kmp-rt-debuginfo - update to 6.4.0-150700.7.75.1
kernel-rt-devel - update to 6.4.0-150700.7.75.1
kernel-zfcpdump-debuginfo - update to 6.4.0-150700.53.81.1
kernel-zfcpdump-debugsource - update to 6.4.0-150700.53.81.1
kernel-zfcpdump - update to 6.4.0-150700.53.81.1
kernel-default-extra-debuginfo - update to 6.4.0-150700.53.81.1
kernel-default-extra - update to 6.4.0-150700.53.81.1
kernel-azure-devel-debuginfo - update to 6.4.0-150700.53.81.1
kernel-azure-debuginfo - update to 6.4.0-150700.53.81.1
kernel-azure-debugsource - update to 6.4.0-150700.53.81.1
kernel-azure-devel - update to 6.4.0-150700.53.81.1
kernel-azure - update to 6.4.0-150700.53.81.1
kernel-default-livepatch-devel - update to 6.4.0-150700.53.81.1
reiserfs-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
reiserfs-kmp-default - update to 6.4.0-150700.53.81.1
kernel-docs - update to 6.4.0-150700.53.81.1
kernel-64kb-devel-debuginfo - update to 6.4.0-150700.53.81.1
kernel-64kb-debuginfo - update to 6.4.0-150700.53.81.1
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 (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, 6.8.0-1070.78
linux-gke (Ubuntu package) - addressed in versions 6.8.0-146.146.1~22.04.1, 6.8.0-146.146.1, 6.8.0-1051.55, 6.8.0-1063.66, 6.8.0-1064.67~22.04.1, 6.8.0-1064.67, 6.8.0-1064.67.1, 6.8.0-1065.73, 6.8.0-1066.67
linux-azure (Ubuntu package) - addressed in versions 6.8.0-1068.75~22.04.1, 6.8.0-1068.75, 6.8.0-1069.77+fips1, 6.8.0-1070.78~22.04.1, 6.8.0-1070.78, 7.0.0-1011.11, 7.0.0-1014.14
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-ibm (Ubuntu package) - update to 7.0.0-1013.13
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