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
openEuler
bpftool
kernel
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

Install security update from vendor's repository.

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

• 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