CVE-2025-68367: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-68367 is a race condition vulnerability in the Linux kernel's macintosh/mac_hid subsystem, specifically in the mac_hid_toggle_emumouse function. The flaw causes a "list_add double add" kernel warning, indicating that a linked list node is being added to a list it is already a member of, which can lead to memory corruption or a kernel crash. It was published on December 24, 2025, and affects multiple stable Linux kernel versions. The CVSS score has not been formally assigned in the available data, and the CVE status is listed as Unknown (CVE.org).

The root cause is a race condition (CWE-362) in the mac_hid_toggle_emumouse function within the macintosh/mac_hid driver. When two concurrent execution paths attempt to toggle mouse emulation simultaneously, a linked list entry can be added twice — a "double add" — corrupting the kernel's internal list structure. The bug was discovered via syzkaller fuzzing, which triggered the __list_add_valid_or_report warning in lib/list_debug.c:35, confirming the double-add condition. Exploitation requires local access to trigger the race condition, typically by rapidly and concurrently invoking the relevant sysctl or input device interface (CVE.org).

Successful exploitation of this race condition can result in kernel memory corruption, leading to a kernel panic (denial of service) or potentially undefined behavior in kernel data structures. Because the vulnerability resides in a kernel driver, it runs with full kernel privileges; however, practical impact is primarily a system crash (availability impact) rather than privilege escalation or data exfiltration, given the nature of the double-add list corruption. Systems running affected Linux kernel versions on hardware or emulated environments with the mac_hid module loaded are at risk (CVE.org).

The Linux kernel maintainers have released patches across multiple stable branches, referenced by commits 1e4b207f, 14c20983, 48a7d427, 61abf8c3, and 583d3652 in the stable kernel tree. Downstream distributions including Debian (linux 6.1.162-1, linux 5.10.249-1), Ubuntu (USN-8179-1/2/3/4, USN-8184-1, USN-8185-1/2, USN-8203-1, USN-8258-1, USN-8260-1, USN-8265-1), SUSE, Oracle Linux, and Red Hat have issued updated kernel packages incorporating the fix. Administrators should update to the latest patched kernel version provided by their distribution as soon as possible; as a temporary workaround, unloading the mac_hid kernel module (if not required) can mitigate exposure (Debian Tracker, Ubuntu USN-8179-1).

The vulnerability has received routine coverage from Linux security aggregators and distribution security teams, with Debian, Ubuntu, SUSE, and Oracle Linux all issuing advisories. No notable researcher commentary or significant social media discussion has been identified beyond standard patch tracking and scanner detection updates from Tenable (Nessus) and Qualys.