CVE-2023-53648: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-53648 is a vulnerability in the Linux kernel's ALSA AC97 audio subsystem, discovered and reported on October 7, 2025. The vulnerability specifically involves a potential NULL pointer dereference in the sndac97mixer function within the sound/pci/ac97/ac97_codec.c file (NVD).

The vulnerability stems from a NULL pointer dereference issue in the sndac97mixer function of the ALSA AC97 audio codec driver. The bug was identified through smatch error detection at line 2354 of sound/pci/ac97/ac97_codec.c, where the 'rac97' variable could potentially be NULL based on a previous assumption at line 2072. The issue requires removing a redundant assignment and adding proper error handling when rac97 is NULL (NVD).

A successful exploitation of this vulnerability could lead to a system crash due to the NULL pointer dereference, potentially causing a denial of service condition in affected Linux systems (NVD).

The vulnerability has been fixed in various Linux distributions. Ubuntu has released patches for multiple kernel versions, including linux-hwe-5.15 (5.15.0-86.96~20.04.1) for Ubuntu 20.04 LTS and several other kernel variants (Ubuntu).