CVE-2022-48702 is a vulnerability identified in the Linux kernel's ALSA (Advanced Linux Sound Architecture) emu10k1 driver, specifically within the snd_emu10k1_pcm_channel_alloc() function. This function is responsible for allocating audio voices (channels) for the emu10k1 sound card chipset. The vulnerability arises due to an out-of-bounds array access caused by improper handling of voice allocation wrapping. The voice allocator sometimes starts allocating near the end of the voice array and wraps around to the beginning. However, snd_emu10k1_pcm_channel_alloc() incorrectly accesses the allocated voices as if no wrap-around occurred, leading to an out-of-bounds read/write when the sum of the first voice index and the requested voice count exceeds the maximum number of voices (64). This flaw can be triggered by requesting multiple audio channels, for example, by running the 'aplay' utility multiple times with 16 channels. The issue was initially discovered using PipeWire, a modern audio server, but can be reproduced with ALSA utilities. The out-of-bounds access is detected by UBSAN (Undefined Behavior Sanitizer) as an array index out-of-bounds error. While the vulnerability does not have known exploits in the wild, it could potentially lead to memory corruption, causing system instability, crashes, or possibly privilege escalation if exploited. The vulnerability affects Linux kernel versions prior to the patch that fixes this out-of-bounds access in the emu10k1 driver. The flaw is specific to the emu10k1 sound card driver, which is used in certain hardware configurations. No CVSS score has been assigned yet, but the vulnerability is significant due to its potential to cause kernel-level memory corruption.

For European organizations, the impact of CVE-2022-48702 depends largely on the deployment of Linux systems using the emu10k1 sound driver. Organizations running Linux servers or workstations with this driver enabled could experience system crashes or kernel panics, leading to denial of service. In environments where audio hardware is used for critical applications (e.g., media production, telecommunication, or embedded systems), this vulnerability could disrupt operations. Although no known exploits exist, the potential for memory corruption raises concerns about privilege escalation or arbitrary code execution, which could compromise system confidentiality and integrity. Given the Linux kernel's widespread use in European enterprises, public sector, and critical infrastructure, unpatched systems could be at risk. However, the vulnerability's impact is somewhat limited by the requirement to interact with the audio subsystem and the specific hardware dependency. Nonetheless, targeted attackers could leverage this flaw in multi-user environments or on systems where untrusted users have access to audio device interfaces.

To mitigate CVE-2022-48702, European organizations should prioritize updating their Linux kernels to versions that include the patch fixing the out-of-bounds access in the emu10k1 driver. Kernel updates should be applied promptly, especially on systems with emu10k1 hardware or where the driver is loaded. System administrators should audit their hardware inventory to identify affected sound cards and disable or blacklist the emu10k1 driver if audio functionality is not required, reducing the attack surface. Additionally, restricting access to audio devices to trusted users only can limit exploitation opportunities. Employing security modules such as SELinux or AppArmor to confine audio subsystem interactions can further reduce risk. Monitoring system logs for unusual kernel warnings or crashes related to snd_emu10k1 can help detect exploitation attempts. Finally, organizations should incorporate this vulnerability into their vulnerability management and patching workflows to ensure timely remediation.