Use-after-free in Linux kernel - CVE-2026-43376

Vulnerability identifier: #VU130811

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-2026-43376

CWE-ID: CWE-416

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 a use-after-free in oplock_info handling in ksmbd when accessing oplock_info under RCU read-side critical sections. A local user can trigger concurrent access to a freed oplock_info structure to cause a denial of service.

The issue can occur when readers access oplock_info after its pointer has been cleared but before a grace period has elapsed.

Linux kernel
Anolis OS
Ubuntu
kernel
python3-perf
perf
kernel-tools-libs-devel
kernel-tools-libs
kernel-tools
kernel-headers
kernel-devel
kernel-debug-devel
kernel-debug
bpftool
linux (Ubuntu package)
linux-hwe-6.17 (Ubuntu package)
linux-azure-fde-6.17 (Ubuntu package)
linux-raspi (Ubuntu package)
linux-azure-6.17 (Ubuntu package)
linux-nvidia-6.17 (Ubuntu package)
linux-oem-6.17 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kernel - update to 6.6.102-6
python3-perf - update to 6.6.102-6
perf - update to 6.6.102-6
kernel-tools-libs-devel - update to 6.6.102-6
kernel-tools-libs - update to 6.6.102-6
kernel-tools - update to 6.6.102-6
kernel-headers - update to 6.6.102-6
kernel-devel - update to 6.6.102-6
kernel-debug-devel - update to 6.6.102-6
kernel-debug - update to 6.6.102-6
bpftool - update to 6.6.102-6
linux (Ubuntu package) - update to 6.17.0-40.40
linux-hwe-6.17 (Ubuntu package) - update to 6.17.0-40.40~24.04.1
linux-azure-fde-6.17 (Ubuntu package) - update to 6.17.0-1018.18~24.04.1
linux-raspi (Ubuntu package) - update to 6.17.0-1021.21
linux-azure-6.17 (Ubuntu package) - update to 6.17.0-1021.21~24.04.1
linux-nvidia-6.17 (Ubuntu package) - update to 6.17.0-1026.26
linux-oem-6.17 (Ubuntu package) - update to 6.17.0-1028.28

• https://git.kernel.org/stable/c/08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c
• https://git.kernel.org/stable/c/1d6abf145615dbfe267ce3b0a271f95e3780e18e
• https://git.kernel.org/stable/c/1dfd062caa165ec9d7ee0823087930f3ab8a6294
• https://git.kernel.org/stable/c/302fef75512b2c8329a3f5efab1ae7ba2562387a
• https://git.kernel.org/stable/c/ce8507ee82c888126d8e7565e27c016308d24cde

• Use-after-free in Linux kernel smb server
• Ubuntu update for linux-oem-6.17
• Ubuntu update for linux
• Ubuntu update for linux-nvidia-6.17
• Ubuntu update for linux-raspi
• Ubuntu update for linux-hwe-6.17
• Ubuntu update for linux-raspi
• Ubuntu update for linux-azure-fde-6.17
• Ubuntu update for linux-azure-6.17
• Anolis OS update for kernel:6.6