CVE-2020-36781 is a vulnerability identified in the Linux kernel's I2C driver for i.MX processors (i2c_imx). The issue arises from improper handling of the power management runtime (pm_runtime) reference counting in the functions i2c_imx_xfer() and i2c_imx_remove(). Specifically, the function pm_runtime_get_sync() increments the pm_runtime reference count even when it fails, but the code does not properly decrement or balance this increment in failure scenarios, leading to a reference count leak. This leak occurs because the code assumes the reference count is not incremented on failure, which is incorrect. The fix involves replacing pm_runtime_get_sync() with pm_runtime_resume_and_get(), which correctly manages the usage counter to keep it balanced. This vulnerability is essentially a resource management bug that can cause the pm_runtime reference count to become inconsistent, potentially leading to improper power management states or resource exhaustion. However, it does not directly enable code execution or privilege escalation. The vulnerability affects specific versions of the Linux kernel source code related to the i2c_imx driver, primarily used in embedded systems with i.MX processors. No known exploits are reported in the wild, and no CVSS score has been assigned yet.

For European organizations, the impact of CVE-2020-36781 is primarily relevant to those using embedded Linux systems with i.MX processors, such as industrial control systems, IoT devices, or specialized hardware running Linux kernels with the affected i2c_imx driver. The reference leak in power management could lead to increased power consumption, reduced battery life, or in worst cases, system instability or denial of service due to resource exhaustion. While this does not directly compromise confidentiality or integrity, availability could be affected if the system enters an unstable power state or crashes. Organizations relying on embedded devices in critical infrastructure, manufacturing, or transportation sectors could experience operational disruptions. However, the lack of known exploits and the technical nature of the vulnerability suggest a lower immediate risk. The impact is more operational and reliability-focused rather than a direct security breach.

To mitigate CVE-2020-36781, organizations should: 1) Apply the official Linux kernel patches that replace pm_runtime_get_sync() with pm_runtime_resume_and_get() in the i2c_imx driver to ensure proper reference count management. 2) For embedded device manufacturers, update firmware and kernel versions to include this fix and perform thorough testing to verify power management stability. 3) Monitor embedded Linux devices for unusual power consumption or instability that could indicate reference count leaks. 4) Implement robust update mechanisms for embedded devices to facilitate timely patch deployment. 5) For critical systems, consider isolating affected devices or applying compensating controls such as watchdog timers to recover from potential hangs or crashes. 6) Maintain an inventory of devices using i.MX processors and assess exposure to this vulnerability to prioritize patching efforts.