CVE-2025-40024
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-10-24

Last updated on: 2025-10-27

Assigner: kernel.org

Description
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.
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Meta Information
Published
2025-10-24
Last Modified
2025-10-27
Generated
2026-05-07
AI Q&A
2025-10-24
EPSS Evaluated
2026-05-05
NVD
EUVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability involves the Linux kernel's vhost subsystem where a task_struct reference was not properly maintained. When a task created by vhost_task_create() exits early due to a signal, its task_struct is released. However, a pending vhost_task_wake() might try to access this now-invalid task_struct, leading to potential use-after-free issues. The fix involves acquiring a reference to the task_struct when creating the thread and releasing it only when the vhost_task is removed, ensuring that vhost_task_wake() accesses a valid task_struct or safely skips the wake if the task has exited.


How can this vulnerability impact me? :

This vulnerability can lead to the Linux kernel attempting to access a task_struct that has already been freed, potentially causing kernel crashes, instability, or undefined behavior. Such issues could be exploited to cause denial of service or other unintended effects on systems running vulnerable kernel versions.


What immediate steps should I take to mitigate this vulnerability?

Update the Linux kernel to a version where the vhost task reference issue is fixed. This ensures that the kernel properly takes a reference on the task_struct in struct vhost_task, preventing use-after-free conditions when tasks exit early. Until the update is applied, avoid using vulnerable vhost features that may trigger this issue.


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