CVE-2025-39861

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

Bluetooth: vhci: Prevent use-after-free by removing debugfs files early

Move the creation of debugfs files into a dedicated function, and ensure they are explicitly removed during vhci_release(), before associated data structures are freed.

Previously, debugfs files such as force_suspend, force_wakeup, and others were created under hdev->debugfs but not removed in vhci_release(). Since vhci_release() frees the backing vhci_data structure, any access to these files after release would result in use-after-free errors.

Although hdev->debugfs is later freed in hci_release_dev(), user can access files after vhci_data is freed but before hdev->debugfs is released.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/1503756fffe76d5aea2371a4b8dee20c3577bcfd
• https://git.kernel.org/stable/c/28010791193a4503f054e8d69a950ef815deb539
• https://git.kernel.org/stable/c/7cc08f2f127b9a66f46ea918e34353811a7cb378
• https://git.kernel.org/stable/c/bd75eba88e88d7b896b0c737b02a74a12afc235f