CVE-2022-48871 is a vulnerability identified in the Linux kernel's Qualcomm GENI serial driver, specifically affecting the handling of the RX FIFO buffer in the qcom-geni-serial driver. The issue arises because the driver's probe function initially allocates memory for the RX FIFO buffer based on a default depth (e.g., 16 words). However, during serial startup, the RX FIFO depth is updated to reflect the actual hardware capabilities (e.g., 32 words) without resizing the allocated buffer accordingly. Consequently, when the RX UART handler reads data, it reads the updated number of words into the originally allocated smaller buffer, causing a slab-out-of-bounds write. This memory corruption can lead to kernel crashes or undefined behavior. The vulnerability is observable in configurations involving Qualcomm Bluetooth HCI UART devices, as demonstrated by kernel address sanitizer (KASAN) reports showing out-of-bounds writes during Bluetooth initialization on Qualcomm Robotics RB5 hardware. The root cause is a mismatch between buffer allocation size and the actual FIFO depth used during runtime. The fix requires ensuring that if the RX FIFO depth changes after the probe phase, the RX FIFO buffer must be resized to prevent out-of-bounds memory access. This vulnerability does not have a CVSS score assigned yet and no known exploits in the wild have been reported as of the publication date.

For European organizations, the impact of CVE-2022-48871 depends largely on the deployment of Linux systems running Qualcomm GENI serial drivers, particularly in embedded or IoT devices that utilize Qualcomm Bluetooth HCI UART interfaces. Potential impacts include system instability, kernel panics, or denial of service due to memory corruption. In critical infrastructure or industrial control systems using affected hardware, this could lead to operational disruptions. While direct remote exploitation is unlikely without local access or specific hardware configurations, attackers with local privileges or physical access could trigger the vulnerability to escalate privileges or disrupt system availability. The vulnerability could also be leveraged as part of a multi-stage attack chain targeting embedded Linux devices in sectors such as manufacturing, robotics, telecommunications, or automotive industries prevalent in Europe. Given the increasing use of Linux-based embedded systems in European industrial environments, this vulnerability poses a moderate risk to operational continuity and security integrity if unpatched.

1. Apply the official Linux kernel patches that address CVE-2022-48871 as soon as they become available from trusted sources or Linux distributions. 2. For organizations using custom or embedded Linux kernels, ensure that the qcom-geni-serial driver is updated to include the fix that resizes the RX FIFO buffer when the FIFO depth changes after probe. 3. Conduct thorough testing of Bluetooth and serial communication subsystems on affected devices after patching to confirm stability and absence of memory corruption. 4. Implement strict access controls to limit local user privileges on devices running affected kernels to reduce the risk of exploitation by unprivileged users. 5. Monitor kernel logs and system behavior for signs of memory corruption or crashes related to the serial driver, especially on devices with Qualcomm Bluetooth hardware. 6. For critical environments, consider network segmentation and device isolation to limit potential impact if exploitation occurs. 7. Maintain up-to-date inventory of devices using Qualcomm GENI serial drivers to prioritize patching and risk assessment.