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CVE-2025-40249

7.8 · HIGH
Published Dec 4, 2025 EPSS 0.14% (4th pctl)

Overview

CVE-2025-40249 is a high-severity vulnerability. It was published on December 4, 2025 and has a CVSS 3.1 base score of 7.8 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

gpio: cdev: make sure the cdev fd is still active before emitting events

With the final call to fput() on a file descriptor, the release action

may be deferred and scheduled on a work queue. The reference count of

that descriptor is still zero and it must not be used. It's possible

that a GPIO change, we want to notify the user-space about, happens

AFTER the reference count on the file descriptor associated with the

character device went down to zero but BEFORE the .release() callback

was called from the workqueue and so BEFORE we unregistered from the

notifier.

Using the regular get_file() routine in this situation triggers the

following warning:

struct file::f_count incremented from zero; use-after-free condition present!

So use the get_file_active() variant that will return NULL on file

descriptors that have been or are being released.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Frequently Asked Questions

What is CVE-2025-40249?

CVE-2025-40249 is a high-severity vulnerability. It was published on December 4, 2025 and has a CVSS 3.1 base score of 7.8 (HIGH).

How severe is CVE-2025-40249?

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2025-40249?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2025-40249?

CyberStrike's AI-powered security agents can automatically detect CVE-2025-40249 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.