Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel - CVE-2026-53265

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Main Vulnerability Database Vulnerabilities #VU135487

Time-of-check Time-of-use (TOCTOU) Race Condition in Linux kernel - CVE-2026-53265

Published: June 26, 2026


Vulnerability identifier: #VU135487
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-2026-53265
CWE-ID: CWE-367
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a check-then-act race condition in smq_invalidate_mapping() in the dm-cache-policy-smq component when invalidating cache blocks concurrently. A local user can trigger concurrent invalidation operations to cause a denial of service.

The issue can corrupt the SMQ queues or hash table and may result in a double free condition.


Affected software

Linux kernel
SUSE Linux Enterprise Server 12 SP5
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise High Performance Computing 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise Live Patching
Ubuntu
kgraft-patch-4_12_14-122_328-default
kernel-default-base
kernel-default-devel
cluster-md-kmp-default
gfs2-kmp-default
ocfs2-kmp-default-debuginfo
gfs2-kmp-default-debuginfo
dlm-kmp-default
ocfs2-kmp-default
kernel-default-base-debuginfo
dlm-kmp-default-debuginfo
cluster-md-kmp-default-debuginfo
kernel-syms
kernel-default-kgraft
kernel-default-debuginfo
kernel-default-kgraft-devel
kernel-default-debugsource
kernel-default
kernel-default-devel-debuginfo
kernel-source
kernel-devel
kernel-macros
kernel-default-man
linux (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-oracle-5.15 (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-gcp (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-gke (Ubuntu package)
linux-azure (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-ibm (Ubuntu package)
linux-nvidia-7.0 (Ubuntu package)
linux-raspi (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

How to mitigate CVE-2026-53265

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
kgraft-patch-4_12_14-122_328-default - update to 1-8.5.1
kernel-default-base - update to 4.12.14-122.328.1
kernel-default-devel - update to 4.12.14-122.328.1
cluster-md-kmp-default - update to 4.12.14-122.328.1
gfs2-kmp-default - update to 4.12.14-122.328.1
ocfs2-kmp-default-debuginfo - update to 4.12.14-122.328.1
gfs2-kmp-default-debuginfo - update to 4.12.14-122.328.1
dlm-kmp-default - update to 4.12.14-122.328.1
ocfs2-kmp-default - update to 4.12.14-122.328.1
kernel-default-base-debuginfo - update to 4.12.14-122.328.1
dlm-kmp-default-debuginfo - update to 4.12.14-122.328.1
cluster-md-kmp-default-debuginfo - update to 4.12.14-122.328.1
kernel-syms - update to 4.12.14-122.328.1
kernel-default-kgraft - update to 4.12.14-122.328.1
kernel-default-debuginfo - update to 4.12.14-122.328.1
kernel-default-kgraft-devel - update to 4.12.14-122.328.1
kernel-default-debugsource - update to 4.12.14-122.328.1
kernel-default - update to 4.12.14-122.328.1
kernel-default-devel-debuginfo - update to 4.12.14-122.328.1
kernel-source - update to 4.12.14-122.328.1
kernel-devel - update to 4.12.14-122.328.1
kernel-macros - update to 4.12.14-122.328.1
kernel-default-man - update to 4.12.14-122.328.1
linux (Ubuntu package) - addressed in versions 5.15.0-195.205~20.04.1, 5.15.0-195.205, 5.15.0-198.208~20.04.1, 5.15.0-198.208+fips1, 5.15.0-1080.84, 5.15.0-1100.108, 5.15.0-1109.111, 5.15.0-1109.114, 5.15.0-1111.115~20.04.1, 5.15.0-1111.115, 5.15.0-1112.118~20.04.1, 5.15.0-1112.118, 5.15.0-1113.119, 5.15.0-1114.120, 5.15.0-1116.125~20.04.1, 5.15.0-1117.124~20.04.1, 5.15.0-1117.124, 5.15.0-1117.124+fips1, 5.15.0-1122.131~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1123.132, 5.15.0-1123.132+fips1, 5.15.0.195.160, 5.15.0.195.205~20.04.1, 5.15.0.198.114, 5.15.0.198.171, 5.15.0.198.208~20.04.1, 5.15.0.1080.83~20.04.1, 5.15.0.1100.99, 5.15.0.1109.105, 5.15.0.1109.113, 5.15.0.1111.108, 5.15.0.1111.115~20.04.1, 5.15.0.1112.111, 5.15.0.1112.118~20.04.1, 5.15.0.1113.112, 5.15.0.1114.110, 5.15.0.1116.120, 5.15.0.1117.113, 5.15.0.1117.120, 5.15.0.1117.124~20.04.1, 5.15.0.1122.131~20.04.1, 5.15.0.1123.107, 5.15.0.1123.121, 5.15.0.1123.132~20.04.1, 7.0.0-31.31~24.04.1, 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12~24.04.1, 7.0.0-1012.12
linux-nvidia (Ubuntu package) - addressed in versions 5.15.0-1112.113, 5.15.0.1112.112, 7.0.0-1018.18
linux-oracle-5.15 (Ubuntu package) - addressed in versions 5.15.0-1114.120~20.04.1, 5.15.0.1114.120~20.04.1
linux-gcp-5.15 (Ubuntu package) - addressed in versions 5.15.0-1118.128~20.04.1, 5.15.0.1118.128~20.04.1
linux-gcp (Ubuntu package) - addressed in versions 5.15.0-1118.128, 5.15.0-1118.128+fips1, 5.15.0.1118.107, 5.15.0.1118.115, 6.8.0-1070.78
linux-azure-fde (Ubuntu package) - addressed in versions 5.15.0-1122.131, 5.15.0.1122.131
linux-gke (Ubuntu package) - addressed in versions 6.8.0-146.146.1~22.04.1, 6.8.0-146.146.1, 6.8.0-1051.55, 6.8.0-1063.66, 6.8.0-1064.67~22.04.1, 6.8.0-1064.67, 6.8.0-1064.67.1, 6.8.0-1065.73, 6.8.0-1066.67
linux-azure (Ubuntu package) - addressed in versions 6.8.0-1068.75~22.04.1, 6.8.0-1068.75, 6.8.0-1069.77+fips1, 6.8.0-1070.78~22.04.1, 6.8.0-1070.78, 7.0.0-1011.11, 7.0.0-1014.14
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1013.13
linux-ibm (Ubuntu package) - update to 7.0.0-1013.13
linux-nvidia-7.0 (Ubuntu package) - update to 7.0.0-1018.18~24.04.1
linux-raspi (Ubuntu package) - update to 7.0.0-1019.19
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2018.18

External References

Related Security Bulletins