Improper locking in Linux kernel - CVE-2026-63980

Vulnerability identifier: #VU138664

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-2026-63980

CWE-ID: CWE-667

Exploitation vector: Local access

Exploit availability: No public exploit available

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

The vulnerability exists due to improper lock handling in the net/handshake subsystem when canceling a TLS handshake from softirq context while the same lock is held in process context on the same CPU. A local user can trigger a TLS handshake cancellation race to cause a denial of service.

The issue results in a deadlock.

Linux kernel
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Workstation Extension 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Micro
SUSE Linux Micro Extras
Public Cloud Module
Legacy Module
Development Tools Module
Basesystem Module
SUSE Real Time Module
SUSE Linux Enterprise Live Patching
Ubuntu
kernel-livepatch-6_4_0-150700_7_75-rt-debuginfo
kernel-livepatch-6_4_0-150700_7_75-rt
kernel-livepatch-SLE15-SP7-RT_Update_20-debugsource
kernel-livepatch-6_4_0-150700_53_81-default
kernel-livepatch-6_4_0-150700_53_81-default-debuginfo
kernel-livepatch-SLE15-SP7_Update_21-debugsource
kernel-obs-build-debugsource
kernel-source
kernel-default-livepatch
kernel-default-debugsource
kernel-default-debuginfo
kernel-kvmsmall-debugsource
kernel-kvmsmall-debuginfo
kernel-default
kernel-default-devel-debuginfo
kernel-rt-livepatch
kernel-64kb
kernel-64kb-debugsource
kernel-64kb-devel
kernel-obs-build
kernel-syms
kernel-default-devel
kernel-rt-debugsource
kernel-rt-debuginfo
kernel-rt
kernel-devel-rt
kernel-source-rt
kernel-kvmsmall
kernel-macros
kernel-devel
kernel-default-base
cluster-md-kmp-rt
ocfs2-kmp-rt
gfs2-kmp-rt-debuginfo
dlm-kmp-rt
kernel-rt-devel
kernel-syms-rt
ocfs2-kmp-rt-debuginfo
gfs2-kmp-rt
dlm-kmp-rt-debuginfo
cluster-md-kmp-rt-debuginfo
kernel-rt-devel-debuginfo
gfs2-kmp-default
dlm-kmp-default
gfs2-kmp-default-debuginfo
ocfs2-kmp-default
dlm-kmp-default-debuginfo
ocfs2-kmp-default-debuginfo
cluster-md-kmp-default
reiserfs-kmp-default-debuginfo
reiserfs-kmp-default
kernel-docs
kernel-64kb-devel-debuginfo
kernel-64kb-debuginfo
kernel-zfcpdump-debuginfo
kernel-zfcpdump-debugsource
kernel-default-livepatch-devel
cluster-md-kmp-default-debuginfo
kernel-zfcpdump
kernel-default-extra
kernel-default-extra-debuginfo
kernel-azure-devel-debuginfo
kernel-azure-debuginfo
kernel-azure-debugsource
kernel-azure-devel
kernel-azure
linux-gke (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-azure (Ubuntu package)
linux-gcp (Ubuntu package)
linux-ibm (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel-livepatch-6_4_0-150700_7_75-rt-debuginfo - 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-SLE15-SP7-RT_Update_20-debugsource - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_53_81-default - 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-SLE15-SP7_Update_21-debugsource - update to 1-150700.15.3.1
kernel-obs-build-debugsource - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-source - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-livepatch - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-debugsource - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-debuginfo - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-kvmsmall-debugsource - update to 6.4.0-52.1
kernel-kvmsmall-debuginfo - update to 6.4.0-52.1
kernel-default - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-devel-debuginfo - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-rt-livepatch - 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-64kb-debugsource - 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
kernel-obs-build - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-syms - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-devel - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
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-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-source-rt - 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-macros - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-devel - addressed in versions 6.4.0-52.1, 6.4.0-150700.53.81.1
kernel-default-base - addressed in versions 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
cluster-md-kmp-rt - update to 6.4.0-150700.7.75.1
ocfs2-kmp-rt - update to 6.4.0-150700.7.75.1
gfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.75.1
dlm-kmp-rt - update to 6.4.0-150700.7.75.1
kernel-rt-devel - 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-debuginfo - update to 6.4.0-150700.7.75.1
gfs2-kmp-default - update to 6.4.0-150700.53.81.1
dlm-kmp-default - update to 6.4.0-150700.53.81.1
gfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
ocfs2-kmp-default - update to 6.4.0-150700.53.81.1
dlm-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
ocfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
cluster-md-kmp-default - 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
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-default-livepatch-devel - update to 6.4.0-150700.53.81.1
cluster-md-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
kernel-zfcpdump - update to 6.4.0-150700.53.81.1
kernel-default-extra - update to 6.4.0-150700.53.81.1
kernel-default-extra-debuginfo - 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
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-nvidia-tegra (Ubuntu package) - update to 6.8.0-1035.38
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, 7.0.0-1009.9, 7.0.0-1010.10
linux-gcp (Ubuntu package) - update to 6.8.0-1070.78
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
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-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16~24.04.1, 7.0.0-1016.16
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

• https://git.kernel.org/stable/c/06ab5978866fc2221b910347fd3e510ca8e7b1a4
• https://git.kernel.org/stable/c/0866569fc36a56f568acd3900d354e3505932e09
• https://git.kernel.org/stable/c/91898de9501a047ba67c6b864dcd403e00bdfbf5
• https://git.kernel.org/stable/c/cc993e0927ec8bd98ea33377ada03295fcda0f24

• Improper locking in Linux kernel handshake
• Ubuntu update for linux-ibm
• Ubuntu update for linux-azure
• Ubuntu update for linux-aws
• Ubuntu update for linux-nvidia-bos
• Ubuntu update for linux-nvidia
• Ubuntu update for linux-gcp-7.0
• SUSE update for the Linux Kernel
• Ubuntu update for linux-oracle-7.0
• Ubuntu update for linux-azure-7.0
• Ubuntu update for linux-nvidia-tegra
• Ubuntu update for linux-gcp
• Ubuntu update for linux-gke
• Ubuntu update for linux-azure
• SUSE update for the Linux Kernel
• SUSE update for the Linux Kernel
• SUSE update for the Linux Kernel
• SUSE update for the Linux Kernel