Use-after-free in Linux kernel - CVE-2026-74401

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Main Vulnerability Database Vulnerabilities #VU142718

Use-after-free in Linux kernel - CVE-2026-74401

Published: August 15, 2026


Vulnerability identifier: #VU142718
CSH Severity: Low
CVSS v4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-74401
CWE-ID: CWE-416
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 use-after-free in the DLM send_queue handling in fs/dlm/midcomms.c when processing a high volume of DLM messages. A local user can trigger heavy DLM message activity to cause a denial of service.

The issue occurs when message sequence numbers in the ordered send queue are not assigned in the required order, leading to refcounting problems.


Affected software

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-lowlatency (Ubuntu package)
linux-raspi (Ubuntu package)
linux-azure (Ubuntu package)
linux-gcp (Ubuntu package)
linux-aws (Ubuntu package)
linux-ibm (Ubuntu package)
linux-oracle (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-realtime (Ubuntu package)
linux-hwe-6.8 (Ubuntu package)
linux-lowlatency-hwe-6.8 (Ubuntu package)
linux-fips (Ubuntu package)
linux-azure-fde-6.8 (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-azure-6.8 (Ubuntu package)
linux-oracle-6.8 (Ubuntu package)
linux-nvidia-lowlatency (Ubuntu package)
linux-gkeop (Ubuntu package)
linux-gke (Ubuntu package)
linux-ibm-6.8 (Ubuntu package)
linux-gcp-6.8 (Ubuntu package)
linux-aws-fips (Ubuntu package)
linux-gcp-fips (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-raspi-realtime (Ubuntu package)
linux-realtime-6.8 (Ubuntu package)
linux-nvidia-bos (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-aws-7.0 (Ubuntu package)
linux-nvidia-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)

How to mitigate CVE-2026-74401

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 6.8.0-147.147, 7.0.0-34.34
linux-lowlatency (Ubuntu package) - update to 6.8.0-147.147.1
linux-raspi (Ubuntu package) - addressed in versions 6.8.0-1068.72, 7.0.0-1020.20
linux-azure (Ubuntu package) - addressed in versions 6.8.0-1071.79, 7.0.0-1016.16, 7.0.0-1017.17
linux-gcp (Ubuntu package) - addressed in versions 6.8.0-1071.79, 7.0.0-1013.13
linux-aws (Ubuntu package) - addressed in versions 6.8.0-1067.70, 7.0.0-1013.13
linux-ibm (Ubuntu package) - addressed in versions 6.8.0-1067.68, 7.0.0-1014.14
linux-oracle (Ubuntu package) - addressed in versions 6.8.0-1064.67, 7.0.0-1012.12
linux-azure-fde (Ubuntu package) - update to 6.8.0-1069.76
linux-nvidia (Ubuntu package) - addressed in versions 6.8.0-1067.70, 7.0.0-1025.26
linux-realtime (Ubuntu package) - addressed in versions 6.8.1-1062.63, 7.0.0-34.34.1
linux-hwe-6.8 (Ubuntu package) - update to 6.8.0-149.149~22.04.1
linux-lowlatency-hwe-6.8 (Ubuntu package) - update to 6.8.0-149.149.1~22.04.1
linux-fips (Ubuntu package) - update to 6.8.0-147.147+fips1
linux-azure-fde-6.8 (Ubuntu package) - update to 6.8.0-1071.78~22.04.1
linux-aws-6.8 (Ubuntu package) - update to 6.8.0-1069.74~22.04.1
linux-nvidia-tegra (Ubuntu package) - update to 6.8.0-1035.38
linux-azure-6.8 (Ubuntu package) - update to 6.8.0-1073.82~22.04.1
linux-oracle-6.8 (Ubuntu package) - update to 6.8.0-1067.71~22.04.1
linux-nvidia-lowlatency (Ubuntu package) - update to 6.8.0-1067.70.1
linux-gkeop (Ubuntu package) - update to 6.8.0-1052.56
linux-gke (Ubuntu package) - addressed in versions 6.8.0-1066.74, 7.0.0-1007.8
linux-ibm-6.8 (Ubuntu package) - update to 6.8.0-1069.70~22.04.1
linux-gcp-6.8 (Ubuntu package) - update to 6.8.0-1073.81~22.04.1
linux-aws-fips (Ubuntu package) - update to 6.8.0-1067.70+fips1
linux-gcp-fips (Ubuntu package) - update to 6.8.0-1071.79+fips1
linux-azure-fips (Ubuntu package) - update to 6.8.0-1071.79+fips1
linux-raspi-realtime (Ubuntu package) - update to 6.8.0-2056.58
linux-realtime-6.8 (Ubuntu package) - update to 6.8.1-1064.65~22.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2022.23
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-34.34~24.04.1
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1013.13~24.04.1
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1012.12~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1014.14
linux-aws-7.0 (Ubuntu package) - update to 7.0.0-1013.13~24.04.1
linux-nvidia-7.0 (Ubuntu package) - update to 7.0.0-1024.25~24.04.1
linux-azure-7.0 (Ubuntu package) - addressed in versions 7.0.0-1016.16~24.04.1, 7.0.0-1017.17~24.04.1

External References

Related Security Bulletins