CVE-2022-48717 is a vulnerability identified in the Linux kernel, specifically within the ASoC (ALSA System on Chip) driver for the max9759 audio amplifier. The issue arises in the function speaker_gain_control_put(), which handles speaker gain control settings. The vulnerability is due to insufficient validation of the 'priv->gain' variable, which can take on negative values. These negative values may originate from user input via the ALSA control interface, specifically through the snd_ctl_elem_write_user() function call chain. Without proper checks, this can lead to an out-of-bounds memory access when the kernel attempts to use the invalid gain value, potentially causing memory corruption or kernel instability. The root cause is a missing boundary check for negative gain values before they are applied, which could be exploited to trigger undefined behavior in the kernel's audio subsystem. The vulnerability has been addressed by adding validation to prevent negative values, thereby mitigating the risk of out-of-bounds access. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet.

For European organizations, this vulnerability poses a risk primarily to systems running vulnerable Linux kernel versions with the affected ASoC max9759 driver enabled. Exploitation could lead to kernel memory corruption, potentially causing system crashes (denial of service) or, in a worst-case scenario, privilege escalation if an attacker can manipulate kernel memory. This could impact servers, embedded devices, or workstations using Linux with this audio driver, especially in industrial, telecommunications, or IoT environments where such hardware is common. The impact on confidentiality and integrity depends on the exploitability of the out-of-bounds access; while no direct data leakage is indicated, kernel instability or privilege escalation could compromise system security. Given the lack of known exploits, the immediate risk is moderate, but the vulnerability should be addressed promptly to prevent future exploitation. Disruption of critical infrastructure or services relying on affected Linux systems could have operational and reputational consequences for European entities.

Organizations should promptly update their Linux kernels to versions that include the patch fixing CVE-2022-48717. If immediate patching is not feasible, administrators should audit systems to identify the presence of the max9759 ASoC driver and disable or blacklist it if not required. Additionally, restricting user access to ALSA control interfaces can reduce the attack surface by preventing unprivileged users from sending crafted inputs to the audio subsystem. Employing kernel hardening techniques such as Kernel Address Space Layout Randomization (KASLR), Kernel Page Table Isolation (KPTI), and enabling security modules like SELinux or AppArmor can further mitigate exploitation risks. Monitoring system logs for unusual kernel errors or crashes related to audio controls can help detect attempted exploitation. Finally, organizations should maintain an inventory of Linux-based devices with audio hardware to prioritize patching and risk management efforts.