Use-after-free in Linux kernel - CVE-2026-43402

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Main Vulnerability Database Vulnerabilities #VU130785

Use-after-free in Linux kernel - CVE-2026-43402

Published: May 8, 2026


Vulnerability identifier: #VU130785
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-2026-43402
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 a use-after-free in kthread exit handling when processing kernel thread termination. A local user can trigger a kernel thread exit path that leaves affinity_node linked after the kthread structure is freed to cause a denial of service.

The issue occurs because a freed kthread structure can be reused as a struct pid object, allowing dangling list operations to corrupt an RCU callback function pointer.


Affected software

Linux kernel
Ubuntu
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)

How to mitigate CVE-2026-43402

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
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

External References

Related Security Bulletins