Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel - CVE-2026-64112

Vulnerability identifier: #VU138528

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-2026-64112

CWE-ID: CWE-367

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 time-of-check time-of-use race condition in the rbd lock_dwork handling in drivers/block/rbd.c when unmapping an image while exclusive lock work is being queued. A local user can trigger image unmap operations during concurrent I/O activity to cause a denial of service.

The issue can result in lock acquisition work executing after device and image release operations have freed or reset internal state.

Linux kernel
openEuler
Ubuntu
kernel-debugsource
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-tools
kernel-source
kernel-headers
kernel-devel
kernel-debuginfo
bpftool-debuginfo
bpftool
kernel
kernel-extra-modules
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-debugsource - addressed in versions 6.6.0-145.1.20.157, 6.6.0-145.3.29.160
python3-perf-debuginfo - addressed in versions 6.6.0-145.1.20.157, 6.6.0-145.3.29.160
python3-perf - addressed in versions 6.6.0-145.1.20.157, 6.6.0-145.3.29.160
perf-debuginfo - addressed in versions 6.6.0-145.1.20.157, 6.6.0-145.3.29.160
perf - addressed in versions 6.6.0-145.1.20.157, 6.6.0-145.3.29.160
kernel-tools-devel - addressed in versions 6.6.0-145.1.20.157, 6.6.0-145.3.29.160
kernel-tools-debuginfo - addressed in versions 6.6.0-145.1.20.157, 6.6.0-145.3.29.160
kernel-tools - addressed in versions 6.6.0-145.1.20.157, 6.6.0-145.3.29.160
kernel-source - addressed in versions 6.6.0-145.1.20.157, 6.6.0-145.3.29.160
kernel-headers - addressed in versions 6.6.0-145.1.20.157, 6.6.0-145.3.29.160
kernel-devel - addressed in versions 6.6.0-145.1.20.157, 6.6.0-145.3.29.160
kernel-debuginfo - addressed in versions 6.6.0-145.1.20.157, 6.6.0-145.3.29.160
bpftool-debuginfo - addressed in versions 6.6.0-145.1.20.157, 6.6.0-145.3.29.160
bpftool - addressed in versions 6.6.0-145.1.20.157, 6.6.0-145.3.29.160
kernel - addressed in versions 6.6.0-145.1.20.157, 6.6.0-145.3.29.160
kernel-extra-modules - update to 6.6.0-145.3.29.160
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/3427d7ae38337066ce88b68302e285d344ab756b
• https://git.kernel.org/stable/c/9400efc76b42c751211974a25c91d2c19c65b01b
• https://git.kernel.org/stable/c/9dcd4f5c99b491c37be90b0bd9988db48225fb75
• https://git.kernel.org/stable/c/9fc75b71fdd38465c76c6f6a884cdd4ae3c72d90

• Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel block driver
• Ubuntu update for linux-ibm
• Ubuntu update for linux-azure
• Ubuntu update for linux-aws
• openEuler 24.03 LTS SP1 update for kernel
• Ubuntu update for linux-nvidia-bos
• Ubuntu update for linux-nvidia
• openEuler 24.03 LTS SP3 update for kernel