CVE-2022-49292 is a vulnerability identified in the Linux kernel's ALSA (Advanced Linux Sound Architecture) OSS (Open Sound System) compatibility layer. The issue arises from an integer overflow during buffer allocation for PCM (Pulse Code Modulation) audio data conversion within the snd_pcm_plug_alloc() function. Specifically, the OSS layer allocates a temporary buffer for data conversion, and when parameters such as the number of audio channels or sample rates are set to high values, the calculated buffer size can exceed the maximum value for a signed 32-bit integer (INT_MAX). This overflow leads to an incorrect buffer size calculation, triggering kernel warnings and potentially causing memory allocation errors or buffer overflows. The vulnerability was detected through syzbot reports indicating INT_MAX overflow at vmalloc() calls. To mitigate this, the patch introduces a strict upper bound of 1MB for period bytes, ensuring the temporary buffer size remains within safe limits. Additionally, the patch employs safe multiplication functions like array_size() and array3_size() to detect and prevent integer overflows during buffer size calculations. This fix is applied at multiple points in the code where buffer sizes are computed, preventing the allocation of excessively large buffers that could lead to kernel instability or exploitation. Although no known exploits are reported in the wild, the vulnerability could potentially be leveraged to cause denial of service (DoS) or kernel crashes if an attacker can manipulate PCM parameters to trigger the overflow. The vulnerability affects Linux kernel versions identified by the commit hash 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and similar builds prior to the patch. Since ALSA and OSS are widely used in Linux distributions, this vulnerability has broad implications for systems relying on Linux audio subsystems.

For European organizations, the impact of CVE-2022-49292 primarily revolves around system stability and potential denial of service. Organizations running Linux-based servers, workstations, or embedded devices that utilize ALSA OSS for audio processing could experience kernel crashes or system instability if the vulnerability is exploited. This could disrupt critical services, especially in environments where Linux is used for multimedia processing, telephony, or other audio-dependent applications. While the vulnerability does not directly expose confidentiality or integrity risks, the resulting denial of service could impact availability, leading to operational downtime. This is particularly relevant for sectors such as telecommunications, media production, and industrial control systems that rely on Linux audio subsystems. Furthermore, the vulnerability could be exploited by local attackers or malicious software with the ability to configure PCM parameters, emphasizing the need for strict access controls. Given the widespread use of Linux in European public sector institutions, research organizations, and enterprises, unpatched systems may be vulnerable to stability issues or targeted disruption attempts. However, the absence of known exploits in the wild and the requirement for specific conditions to trigger the overflow somewhat limit the immediate risk level.

To mitigate CVE-2022-49292, European organizations should: 1) Apply the official Linux kernel patch that introduces the 1MB upper bound on period bytes and uses safe multiplication functions to prevent integer overflows. This patch is critical to prevent buffer allocation overflows in the ALSA OSS layer. 2) Update Linux distributions to the latest kernel versions that include this fix, prioritizing systems with audio processing capabilities or those exposed to untrusted users. 3) Restrict access to audio device configuration interfaces to trusted users only, minimizing the risk of malicious parameter manipulation. 4) Monitor kernel logs for WARN_ON() messages related to vmalloc() or snd_pcm_plug_alloc(), which may indicate attempts to trigger the vulnerability. 5) For embedded or specialized Linux devices, coordinate with vendors to ensure firmware or kernel updates are applied promptly. 6) Implement system integrity monitoring to detect unusual kernel crashes or reboots that could be symptomatic of exploitation attempts. 7) Educate system administrators about the vulnerability and the importance of timely patching, especially in environments where audio subsystems are critical. These steps go beyond generic advice by focusing on kernel patching, access control, and proactive monitoring specific to this vulnerability.