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.

CVSS Scores

EPSS Scores

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Meta Information

Published

2025-10-24

Last Modified

2025-10-27

Generated

2026-07-06

AI Q&A

2025-10-24

EPSS Evaluated

2026-07-05

NVD

CVE-2025-40024

EUVD

EUVD-2025-35835

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

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.

Impact Analysis

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.

Mitigation Strategies

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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