Executive brief
A vulnerability was identified in the Linux kernel's audio driver for C-Media PCI sound cards. Under specific conditions where the system runs out of memory, the driver could attempt to access an invalid memory address, potentially causing a system crash or instability. This issue primarily affects the reliability of systems using this specific hardware.
Technical details
A NULL pointer dereference vulnerability exists in the Linux kernel ALSA (Advanced Linux Sound Architecture) subsystem within the cmipci driver (sound/pci/cmipci.c). The function snd_cmipci_spdif_controls() calls snd_ctl_new1() to allocate new control structures but fails to verify if the returned pointer is NULL. If memory allocation fails, the driver proceeds to dereference the NULL pointer when initializing kctl->id.device. This is a local vulnerability that can lead to a kernel oops or system crash (Denial of Service). Patches have been released across various stable kernel branches (e.g., 6.1.178, 6.6.145, 6.12.96).
Affected products
- Linux Linux 6.1.34 to 6.1.178; 6.3.8 to 6.4; 6.4 and later versions prior to 6.6.145, 6.12.96, 6.18.39, and 7.1.4
Timeline
- 2026-07-25: disclosed
- 2026-07-25: advisory
References
- https://git.kernel.org/stable/c/4dd5b0b1a52a8d6e59a3f217204817228ce0238b
- https://git.kernel.org/stable/c/67e9ea92cd598cba1783ff701553c776a6cedee9
- https://git.kernel.org/stable/c/8825a06bfa7932a7a74dec01669d405df0b47286
- https://git.kernel.org/stable/c/af2b009b773bc42995546507963e5e78970dc3ed
- https://git.kernel.org/stable/c/b44888c33c4f11277d0e5e023338f2740232a4ed
- https://git.kernel.org/stable/c/c205bd1b28fb7e5f1061a4e78813fad7d315cb3e