Improper locking in Linux kernel - CVE-2026-52946

Vulnerability identifier: #VU135430

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-52946

CWE-ID: CWE-667

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper locking in fs/fcntl.c when handling TCP urgent data signaling for a process group. A remote attacker can send specially crafted TCP URG packets to cause a denial of service.

The issue occurs when FASYNC is configured for a process group.

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 Real Time 15
SUSE Linux Enterprise Workstation Extension 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Availability Extension 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Live Patching
Public Cloud Module
Legacy Module
Development Tools Module
Basesystem Module
openEuler
kgraft-patch-4_12_14-122_328-default
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
ocfs2-kmp-default
kernel-default
kernel-default-debugsource
kernel-default-kgraft-devel
kernel-default-debuginfo
kernel-default-kgraft
kernel-syms
cluster-md-kmp-default-debuginfo
dlm-kmp-default-debuginfo
kernel-default-base-debuginfo
dlm-kmp-default
gfs2-kmp-default-debuginfo
ocfs2-kmp-default-debuginfo
gfs2-kmp-default
cluster-md-kmp-default
kernel-default-devel
kernel-default-base
kernel-default-devel-debuginfo
kernel-source
kernel-devel
kernel-macros
kernel-default-man
bpftool
kernel
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-headers
kernel-debugsource
kernel-debuginfo
bpftool-debuginfo
reiserfs-kmp-default-debuginfo
kernel-default-livepatch
kernel-default-livepatch-devel
kernel-azure
kernel-azure-devel
kernel-azure-debugsource
kernel-azure-debuginfo
kernel-azure-devel-debuginfo
kernel-default-extra-debuginfo
kernel-default-extra
kernel-64kb-debuginfo
kernel-zfcpdump
kernel-zfcpdump-debugsource
kernel-zfcpdump-debuginfo
kernel-64kb
kernel-64kb-devel
kernel-64kb-devel-debuginfo
kernel-64kb-debugsource
kernel-docs
kernel-obs-build
kernel-obs-build-debugsource
reiserfs-kmp-default

Install security update from vendor's repository.

kgraft-patch-4_12_14-122_328-default - update to 1-8.5.1
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
ocfs2-kmp-default - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
kernel-default - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
kernel-default-debugsource - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
kernel-default-kgraft-devel - update to 4.12.14-122.328.1
kernel-default-debuginfo - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
kernel-default-kgraft - update to 4.12.14-122.328.1
kernel-syms - addressed in versions 4.12.14-122.328.1, 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
dlm-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
ocfs2-kmp-default-debuginfo - 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
cluster-md-kmp-default - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
kernel-default-devel - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
kernel-default-base - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1.150700.17.45.1
kernel-default-devel-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, 6.4.0-150700.53.81.1
kernel-devel - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
kernel-macros - addressed in versions 4.12.14-122.328.1, 6.4.0-150700.53.81.1
kernel-default-man - update to 4.12.14-122.328.1
bpftool - addressed in versions 5.10.0-321.0.0.223, 6.6.0-145.1.20.157
kernel - addressed in versions 5.10.0-321.0.0.223, 6.6.0-145.1.20.157
python3-perf-debuginfo - addressed in versions 5.10.0-321.0.0.223, 6.6.0-145.1.20.157
python3-perf - addressed in versions 5.10.0-321.0.0.223, 6.6.0-145.1.20.157
perf-debuginfo - addressed in versions 5.10.0-321.0.0.223, 6.6.0-145.1.20.157
perf - addressed in versions 5.10.0-321.0.0.223, 6.6.0-145.1.20.157
kernel-tools-devel - addressed in versions 5.10.0-321.0.0.223, 6.6.0-145.1.20.157
kernel-tools-debuginfo - addressed in versions 5.10.0-321.0.0.223, 6.6.0-145.1.20.157
kernel-tools - addressed in versions 5.10.0-321.0.0.223, 6.6.0-145.1.20.157
kernel-source - addressed in versions 5.10.0-321.0.0.223, 6.6.0-145.1.20.157
kernel-headers - addressed in versions 5.10.0-321.0.0.223, 6.6.0-145.1.20.157
kernel-devel - addressed in versions 5.10.0-321.0.0.223, 6.6.0-145.1.20.157
kernel-debugsource - addressed in versions 5.10.0-321.0.0.223, 6.6.0-145.1.20.157
kernel-debuginfo - addressed in versions 5.10.0-321.0.0.223, 6.6.0-145.1.20.157
bpftool-debuginfo - addressed in versions 5.10.0-321.0.0.223, 6.6.0-145.1.20.157
reiserfs-kmp-default-debuginfo - update to 6.4.0-150700.53.81.1
kernel-default-livepatch - update to 6.4.0-150700.53.81.1
kernel-default-livepatch-devel - update to 6.4.0-150700.53.81.1
kernel-azure - update to 6.4.0-150700.53.81.1
kernel-azure-devel - update to 6.4.0-150700.53.81.1
kernel-azure-debugsource - update to 6.4.0-150700.53.81.1
kernel-azure-debuginfo - update to 6.4.0-150700.53.81.1
kernel-azure-devel-debuginfo - 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-64kb-debuginfo - update to 6.4.0-150700.53.81.1
kernel-zfcpdump - update to 6.4.0-150700.53.81.1
kernel-zfcpdump-debugsource - update to 6.4.0-150700.53.81.1
kernel-zfcpdump-debuginfo - update to 6.4.0-150700.53.81.1
kernel-64kb - update to 6.4.0-150700.53.81.1
kernel-64kb-devel - update to 6.4.0-150700.53.81.1
kernel-64kb-devel-debuginfo - update to 6.4.0-150700.53.81.1
kernel-64kb-debugsource - update to 6.4.0-150700.53.81.1
kernel-docs - update to 6.4.0-150700.53.81.1
kernel-obs-build - update to 6.4.0-150700.53.81.1
kernel-obs-build-debugsource - update to 6.4.0-150700.53.81.1
reiserfs-kmp-default - update to 6.4.0-150700.53.81.1

• https://git.kernel.org/stable/c/1bee417678f1135e35b25a37734db46aa94258d2
• https://git.kernel.org/stable/c/20a93e397abe850c49b6fa0e8cc827b5f634a8f5
• https://git.kernel.org/stable/c/32dbd5ce4be3a3ed7e00f8af18795cc84fc50a33
• https://git.kernel.org/stable/c/36c1b57b2ecf3c61ac93f5f07bd29b6f21e226ed
• https://git.kernel.org/stable/c/54626335ea4174ab2d9a183b511d825f6765e47b
• https://git.kernel.org/stable/c/897d6a7247739fb1528f98c575df4f2e5de7f994
• https://git.kernel.org/stable/c/b5fa9e32fb6718f70c986ee14dd5d01b4846f331
• https://git.kernel.org/stable/c/bfcc8e8d8a495bb34cae9e620adfb75fb13a3954

• Improper locking in Linux kernel fs
• openEuler 22.03 LTS SP4 update for kernel
• openEuler 24.03 LTS SP1 update for kernel
• SUSE update for the Linux Kernel
• SUSE update for the Linux Kernel