Bug 2406201 (CVE-2025-40024)

Summary: CVE-2025-40024 kernel: vhost: Take a reference on the task in struct vhost_task
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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Description OSIDB Bzimport 2025-10-24 13:01:19 UTC 
In the Linux kernel, the following vulnerability has been resolved:

vhost: Take a reference on the task in struct vhost_task.

vhost_task_create() creates a task and keeps a reference to its
task_struct. That task may exit early via a signal and its task_struct
will be released.
A pending vhost_task_wake() will then attempt to wake the task and
access a task_struct which is no longer there.

Acquire a reference on the task_struct while creating the thread and
release the reference while the struct vhost_task itself is removed.
If the task exits early due to a signal, then the vhost_task_wake() will
still access a valid task_struct. The wake is safe and will be skipped
in this case.
Comment 1 Keith Grant 2025-10-24 13:49:06 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025102404-CVE-2025-40024-8739@gregkh/T