CVE-2017-17975 in Linux
Summary
by MITRE
Use-after-free in the usbtv_probe function in drivers/media/usb/usbtv/usbtv-core.c in the Linux kernel through 4.14.10 allows attackers to cause a denial of service (system crash) or possibly have unspecified other impact by triggering failure of audio registration, because a kfree of the usbtv data structure occurs during a usbtv_video_free call, but the usbtv_video_fail label's code attempts to both access and free this data structure.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 09/14/2025
The vulnerability described in CVE-2017-17975 represents a critical use-after-free condition within the Linux kernel's USB TV driver subsystem, specifically affecting the usbtv_probe function in drivers/media/usb/usbtv/usbtv-core.c. This flaw exists in kernel versions through 4.14.10 and demonstrates a classic memory safety issue that can lead to system instability and potential privilege escalation. The vulnerability occurs when the kernel attempts to handle USB TV device registration and fails to properly manage memory allocation and deallocation sequences during error handling paths.
The technical flaw manifests when the usbtv_video_fail label's code path attempts to access and free a usbtv data structure that has already been freed during a usbtv_video_free call. This creates a scenario where memory that has been deallocated is accessed, leading to undefined behavior and potential system crashes. The memory management error occurs specifically during audio registration failure conditions, where the kernel's error handling logic fails to account for the fact that the data structure has already been freed, resulting in a double-free condition or access to freed memory. This type of vulnerability is classified under CWE-416 as Use After Free, which is a well-documented and dangerous class of memory safety issues that can be exploited for privilege escalation or system compromise.
The operational impact of this vulnerability extends beyond simple denial of service, as the unspecified other impacts could include privilege escalation or arbitrary code execution depending on the exploitation context. When an attacker can trigger the audio registration failure path, they can cause the kernel to execute code that accesses freed memory, potentially leading to kernel memory corruption. This type of vulnerability is particularly concerning because it operates at the kernel level where privilege escalation is possible, and the system crash can be leveraged as a denial of service vector against critical infrastructure. The ATT&CK framework would categorize this under T1068 for privilege escalation and T1499 for network denial of service, as the vulnerability can be exploited to compromise system integrity and availability.
Mitigation strategies for CVE-2017-17975 require immediate kernel updates to versions that contain the patched usbtv-core.c implementation. System administrators should prioritize patching affected kernel versions to prevent exploitation, as the vulnerability can be triggered remotely through USB device connections. Additionally, implementing runtime protections such as kernel address space layout randomization and stack canaries can help detect and prevent exploitation attempts. The fix typically involves ensuring proper memory management in error handling paths by preventing access to freed data structures and maintaining proper reference counting mechanisms. Organizations should also implement monitoring for USB device connections and unusual kernel behavior patterns that could indicate exploitation attempts, as the vulnerability requires specific conditions to be met but can have severe consequences when successfully exploited.