SB20260508136 - Use-after-free in Linux kernel kthread exit handling

Description

This security bulletin contains information about 1 vulnerability.

1) Use-after-free (CVE-ID: CVE-2026-43402)

CWE-ID: CWE-416 - Use After Free

CVSSv4: 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/E:U/U:Clear

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.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/28aaa9c39945b7925a1cc1d513c8f21ed38f5e4f
• https://git.kernel.org/stable/c/4729c7b00a347fd37d0cbc265b85f2884c3e06b6
• https://git.kernel.org/stable/c/5a591d7a5e48d30100943940a30a6ab41b15c672