CVE-2025-21928

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

HID: intel-ish-hid: Fix use-after-free issue in ishtp_hid_remove()

The system can experience a random crash a few minutes after the driver is removed. This issue occurs due to improper handling of memory freeing in the ishtp_hid_remove() function.

The function currently frees the driver_data directly within the loop that destroys the HID devices, which can lead to accessing freed memory. Specifically, hid_destroy_device() uses driver_data when it calls hid_ishtp_set_feature() to power off the sensor, so freeing driver_data beforehand can result in accessing invalid memory.

This patch resolves the issue by storing the driver_data in a temporary variable before calling hid_destroy_device(), and then freeing the driver_data after the device is destroyed.

Weakness

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

Affected Software

Extended Description

The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:

In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Potential Mitigations

References

• https://git.kernel.org/stable/c/01b18a330cda61cc21423a7d1af92cf31ded8f60
• https://git.kernel.org/stable/c/07583a0010696a17fb0942e0b499a62785c5fc9f
• https://git.kernel.org/stable/c/0c1fb475ef999d6c22fc3f963fdf20cb3ed1b03d
• https://git.kernel.org/stable/c/560f4d1299342504a6ab8a47f575b5e6b8345ada
• https://git.kernel.org/stable/c/cf1a6015d2f6b1f0afaa0fd6a0124ff2c7943394
• https://git.kernel.org/stable/c/d3faae7f42181865c799d88c5054176f38ae4625
• https://git.kernel.org/stable/c/dea6a349bcaf243fff95dfd0428a26be6a0fb44e
• https://git.kernel.org/stable/c/eb0695d87a81e7c1f0509b7d8ee7c65fbc26aec9