Improper locking in Linux kernel - CVE-2026-64528

Vulnerability identifier: #VU139406

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-2026-64528

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 s3c24xx_serial_rx_enable() and s3c24xx_serial_rx_disable() when console flow control is engaged during transmit state changes. A local user can trigger the affected serial driver code path to cause a denial of service.

The issue occurs because the code attempts to reacquire the same non-recursive spinlock while it is already held on the same CPU.

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 High Availability Extension 15
SUSE Linux Enterprise Desktop 15
Basesystem Module
Development Tools Module
Legacy Module
Public Cloud Module
SUSE Linux Enterprise Live Patching
SUSE Real Time Module
Ubuntu
kernel-livepatch-6_4_0-150700_7_78-rt-debuginfo
kernel-livepatch-6_4_0-150700_7_78-rt
kernel-livepatch-SLE15-SP7-RT_Update_21-debugsource
kernel-livepatch-6_4_0-150700_53_84-default-debuginfo
kernel-livepatch-SLE15-SP7_Update_22-debugsource
kernel-livepatch-6_4_0-150700_53_84-default
kernel-rt
ocfs2-kmp-rt-debuginfo
cluster-md-kmp-rt-debuginfo
kernel-rt-debuginfo
kernel-rt-devel-debuginfo
kernel-rt-devel
kernel-syms-rt
kernel-rt-debugsource
cluster-md-kmp-rt
dlm-kmp-rt-debuginfo
gfs2-kmp-rt
gfs2-kmp-rt-debuginfo
ocfs2-kmp-rt
dlm-kmp-rt
kernel-devel-rt
kernel-source-rt
kernel-default
kernel-default-devel
kernel-64kb
kernel-default-devel-debuginfo
kernel-devel
kernel-macros
kernel-zfcpdump
kernel-zfcpdump-debugsource
kernel-zfcpdump-debuginfo
reiserfs-kmp-default-debuginfo
ocfs2-kmp-default-debuginfo
kernel-default-debuginfo
dlm-kmp-default-debuginfo
kernel-default-debugsource
cluster-md-kmp-default
gfs2-kmp-default-debuginfo
dlm-kmp-default
gfs2-kmp-default
ocfs2-kmp-default
cluster-md-kmp-default-debuginfo
kernel-64kb-devel-debuginfo
kernel-default-extra-debuginfo
kernel-default-extra
kernel-azure-devel-debuginfo
kernel-azure-debuginfo
kernel-azure-devel
kernel-azure-debugsource
kernel-azure
kernel-default-livepatch
kernel-default-livepatch-devel
reiserfs-kmp-default
kernel-source
kernel-obs-build-debugsource
kernel-obs-build
kernel-syms
kernel-docs
kernel-64kb-devel
kernel-64kb-debugsource
kernel-64kb-debuginfo
kernel-default-base
linux (Ubuntu package)
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-aws (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-azure-7.0 (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_78-rt-debuginfo - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_7_78-rt - update to 1-150700.1.3.1
kernel-livepatch-SLE15-SP7-RT_Update_21-debugsource - update to 1-150700.1.3.1
kernel-livepatch-6_4_0-150700_53_84-default-debuginfo - update to 1-150700.15.3.1
kernel-livepatch-SLE15-SP7_Update_22-debugsource - update to 1-150700.15.3.1
kernel-livepatch-6_4_0-150700_53_84-default - update to 1-150700.15.3.1
kernel-rt - update to 6.4.0-150700.7.78.1
ocfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.78.1
cluster-md-kmp-rt-debuginfo - update to 6.4.0-150700.7.78.1
kernel-rt-debuginfo - update to 6.4.0-150700.7.78.1
kernel-rt-devel-debuginfo - update to 6.4.0-150700.7.78.1
kernel-rt-devel - update to 6.4.0-150700.7.78.1
kernel-syms-rt - update to 6.4.0-150700.7.78.1
kernel-rt-debugsource - update to 6.4.0-150700.7.78.1
cluster-md-kmp-rt - update to 6.4.0-150700.7.78.1
dlm-kmp-rt-debuginfo - update to 6.4.0-150700.7.78.1
gfs2-kmp-rt - update to 6.4.0-150700.7.78.1
gfs2-kmp-rt-debuginfo - update to 6.4.0-150700.7.78.1
ocfs2-kmp-rt - update to 6.4.0-150700.7.78.1
dlm-kmp-rt - update to 6.4.0-150700.7.78.1
kernel-devel-rt - update to 6.4.0-150700.7.78.1
kernel-source-rt - update to 6.4.0-150700.7.78.1
kernel-default - update to 6.4.0-150700.53.84.1
kernel-default-devel - update to 6.4.0-150700.53.84.1
kernel-64kb - update to 6.4.0-150700.53.84.1
kernel-default-devel-debuginfo - update to 6.4.0-150700.53.84.1
kernel-devel - update to 6.4.0-150700.53.84.1
kernel-macros - update to 6.4.0-150700.53.84.1
kernel-zfcpdump - update to 6.4.0-150700.53.84.1
kernel-zfcpdump-debugsource - update to 6.4.0-150700.53.84.1
kernel-zfcpdump-debuginfo - update to 6.4.0-150700.53.84.1
reiserfs-kmp-default-debuginfo - update to 6.4.0-150700.53.84.1
ocfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.84.1
kernel-default-debuginfo - update to 6.4.0-150700.53.84.1
dlm-kmp-default-debuginfo - update to 6.4.0-150700.53.84.1
kernel-default-debugsource - update to 6.4.0-150700.53.84.1
cluster-md-kmp-default - update to 6.4.0-150700.53.84.1
gfs2-kmp-default-debuginfo - update to 6.4.0-150700.53.84.1
dlm-kmp-default - update to 6.4.0-150700.53.84.1
gfs2-kmp-default - update to 6.4.0-150700.53.84.1
ocfs2-kmp-default - update to 6.4.0-150700.53.84.1
cluster-md-kmp-default-debuginfo - update to 6.4.0-150700.53.84.1
kernel-64kb-devel-debuginfo - update to 6.4.0-150700.53.84.1
kernel-default-extra-debuginfo - update to 6.4.0-150700.53.84.1
kernel-default-extra - update to 6.4.0-150700.53.84.1
kernel-azure-devel-debuginfo - update to 6.4.0-150700.53.84.1
kernel-azure-debuginfo - update to 6.4.0-150700.53.84.1
kernel-azure-devel - update to 6.4.0-150700.53.84.1
kernel-azure-debugsource - update to 6.4.0-150700.53.84.1
kernel-azure - update to 6.4.0-150700.53.84.1
kernel-default-livepatch - update to 6.4.0-150700.53.84.1
kernel-default-livepatch-devel - update to 6.4.0-150700.53.84.1
reiserfs-kmp-default - update to 6.4.0-150700.53.84.1
kernel-source - update to 6.4.0-150700.53.84.1
kernel-obs-build-debugsource - update to 6.4.0-150700.53.84.1
kernel-obs-build - update to 6.4.0-150700.53.84.1
kernel-syms - update to 6.4.0-150700.53.84.1
kernel-docs - update to 6.4.0-150700.53.84.1
kernel-64kb-devel - update to 6.4.0-150700.53.84.1
kernel-64kb-debugsource - update to 6.4.0-150700.53.84.1
kernel-64kb-debuginfo - update to 6.4.0-150700.53.84.1
kernel-default-base - update to 6.4.0-150700.53.84.1.150700.17.47.1
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
linux-nvidia (Ubuntu package) - addressed in versions 5.15.0-1112.113, 5.15.0.1112.112, 7.0.0-1016.16~24.04.1, 7.0.0-1016.16
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
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
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-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

• https://git.kernel.org/stable/c/10014eb7eee351f7b587f8ac85830f0c9343cb9a
• https://git.kernel.org/stable/c/14143ec10d69f42806b5d7b046f0fd1b835831ae
• https://git.kernel.org/stable/c/9c92b42207978559e32903c3098aaf5c5b5788b2
• https://git.kernel.org/stable/c/9fd48937046efc9abb89379d63ee9cc5c661d711
• https://git.kernel.org/stable/c/a3bb136bff5e6a5e48cdd813246c9c4686feaaa9
• https://git.kernel.org/stable/c/a9c22e0f93ba18322a6623ecdda2f0cd858ca350
• https://git.kernel.org/stable/c/ee9eb72be95490602c493db050c73d925c3a4d74
• https://git.kernel.org/stable/c/f4c3e63fa8639aedf96fb200d9939945a9eed51e

• Improper locking in Linux kernel tty serial driver
• Ubuntu update for linux-aws
• Ubuntu update for linux-nvidia-bos
• Ubuntu update for linux-nvidia
• Ubuntu update for linux-gcp-7.0
• Ubuntu update for linux-oracle-7.0
• Ubuntu update for linux-azure-7.0
• Ubuntu update for linux-gcp
• Ubuntu update for linux-gke
• Ubuntu update for linux-nvidia
• Ubuntu update for linux-azure
• Ubuntu update for linux-gcp
• Ubuntu update for linux-gcp-5.15
• Ubuntu update for linux-oracle-5.15
• Ubuntu update for linux
• SUSE update for the Linux Kernel
• SUSE update for the Linux Kernel