CVE-2024-46683: 
Linux Debian vulnerability analysis and mitigation

CVE-2024-46683 affects the Linux kernel's DRM/XE driver. The vulnerability was discovered in the preempt fence functionality where a Use-After-Free (UAF) condition could occur. The issue exists in Linux kernel versions from 6.10 up to (excluding) 6.10.8, and various 6.11 release candidates (rc1 through rc5) (NVD).

The vulnerability stems from a design flaw in the fence lock implementation within the queue structure. The fence lock is part of the queue, and according to the design, any entity locking the fence should maintain a reference to the queue to prevent it from being freed. However, the implementation signals the fence and drops the queue reference, while a waiter might still be waiting on the fence. When the waiter wakes up and attempts to grab the lock before checking the fence state, the queue might have already been freed, leading to a Use-After-Free condition (Kernel Patch). The vulnerability has been assigned a CVSS v3.1 base score of 7.8 (HIGH) with vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (NVD).

The vulnerability could allow an attacker with local access and low privileges to potentially cause a Use-After-Free condition in the kernel's DRM/XE driver, which could lead to privilege escalation, information disclosure, or system crashes (NVD).

The issue has been fixed by moving the fence lock into the fence itself to prevent lifetime issues. The fix involves removing the lock from the queue structure and adding it to the fence structure, ensuring proper synchronization without the risk of Use-After-Free. Users should update to Linux kernel version 6.10.8 or later, or apply the available patches (Kernel Patch).