CVE-2025-40024: vhost: Take a reference on the task in struct vhost_task.

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-10-24 · updated 2026-10-19

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.

Affected products

Linux kernel: 6.4 — fixed in 6.17

How to fix

Upgrade to a fixed version: Linux kernel 6.17. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2025-40024 or the next vulnerability affects your stack