CVE-2020-36783 is a vulnerability identified in the Linux kernel specifically related to the i2c subsystem, more precisely the img-scb driver component. The issue arises from improper handling of the power management (PM) reference count when the function pm_runtime_get_sync fails. Normally, pm_runtime_get_sync increments the PM reference count to indicate active usage of a device, and this count should be balanced by a corresponding decrement to avoid resource leaks. However, in the affected code paths within img_i2c_xfer and img_i2c_init functions, pm_runtime_get_sync increments the reference count even on failure, but the code does not decrement it accordingly, leading to a reference leak. This leak can cause the PM usage counter to become unbalanced, potentially preventing the device from entering low power states or causing resource exhaustion over time. The fix replaces pm_runtime_get_sync with pm_runtime_resume_and_get, which correctly manages the usage counter by only incrementing it when the device is resumed successfully, thus maintaining proper reference counting. Although this vulnerability does not directly allow code execution or privilege escalation, it can degrade system stability and power management efficiency, especially on devices relying on the img-scb i2c driver. No known exploits are reported in the wild as of the publication date, and no CVSS score has been assigned yet.

For European organizations, the impact of CVE-2020-36783 primarily concerns systems running Linux kernels with the affected img-scb i2c driver, which is often found in embedded devices or specialized hardware platforms. The vulnerability could lead to resource leaks causing degraded device performance, increased power consumption, or potential device unavailability due to improper power management. This is particularly relevant for industries relying on embedded Linux systems such as telecommunications, industrial automation, automotive, and IoT deployments prevalent in Europe. Over time, the reference leak could cause system instability or failures, impacting operational continuity and increasing maintenance costs. While it does not directly compromise confidentiality or integrity, the availability and reliability of critical infrastructure components could be affected, which is a significant concern for sectors like energy, manufacturing, and transportation. European organizations with large-scale Linux deployments should assess their exposure, especially where power management and device uptime are critical.

To mitigate this vulnerability, organizations should apply the official Linux kernel patches that replace pm_runtime_get_sync with pm_runtime_resume_and_get in the img-scb i2c driver code. This ensures proper reference counting and prevents resource leaks. System administrators should verify that their Linux kernel versions include this fix or upgrade to a patched kernel release. For embedded devices or custom Linux distributions, vendors should be contacted to provide updated firmware or kernel versions incorporating the patch. Additionally, monitoring tools should be employed to detect abnormal power management behavior or resource leaks that could indicate unpatched systems. Implementing rigorous testing of power management functions during kernel updates can help identify regressions related to this issue. Since no known exploits exist, prioritizing patch deployment in environments where device availability and power efficiency are critical is advised. Finally, maintaining an inventory of devices using the img-scb i2c driver will help focus remediation efforts effectively.