Race condition in Linux kernel - CVE-2026-64136

Vulnerability identifier: #VU138499

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-2026-64136

CWE-ID: CWE-362

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 synchronization in smb2_find_smb_sess_tcon_unlocked() when handling SMB tree connection lookups. A local user can trigger concurrent access to corrupt tc_count handling and cause a denial of service.

Linux kernel
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
openEuler
Ubuntu
kernel-debuginfo
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-source
kernel-headers
kernel-extra-modules
kernel-devel
kernel-debugsource
bpftool-debuginfo
bpftool
kernel
kernel (Red Hat package)
linux-ibm (Ubuntu package)
linux-aws (Ubuntu package)
linux-azure (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-debuginfo - update to 6.6.0-145.3.29.160
python3-perf-debuginfo - update to 6.6.0-145.3.29.160
python3-perf - update to 6.6.0-145.3.29.160
perf-debuginfo - update to 6.6.0-145.3.29.160
perf - update to 6.6.0-145.3.29.160
kernel-tools-devel - update to 6.6.0-145.3.29.160
kernel-tools-debuginfo - update to 6.6.0-145.3.29.160
kernel-tools - update to 6.6.0-145.3.29.160
kernel-source - update to 6.6.0-145.3.29.160
kernel-headers - update to 6.6.0-145.3.29.160
kernel-extra-modules - update to 6.6.0-145.3.29.160
kernel-devel - update to 6.6.0-145.3.29.160
kernel-debugsource - update to 6.6.0-145.3.29.160
bpftool-debuginfo - update to 6.6.0-145.3.29.160
bpftool - update to 6.6.0-145.3.29.160
kernel - update to 6.6.0-145.3.29.160
kernel (Red Hat package) - update to 6.12.0-211.50.1.el10_2
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-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

• https://git.kernel.org/stable/c/13fb413ae22a37c69341918a6d651d19a9b0b9b7
• https://git.kernel.org/stable/c/4d8690dace005a38e6dbde9ecce2da3ad85c7c41
• https://git.kernel.org/stable/c/7df1df6f40c0720d30206aa35c0343b962350e0d
• https://git.kernel.org/stable/c/bf4ebdb19ff9b3cdf992b50715fe61633327416a
• https://git.kernel.org/stable/c/e374f4e496fef8168784f93a4477d67be34485fd

• Race condition in Linux kernel smb client
• 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
• Red Hat Enterprise Linux 10 update for kernel
• openEuler 24.03 LTS SP3 update for kernel