CVE-2022-50110 in Linux
Summary
by MITRE • 06/18/2025
In the Linux kernel, the following vulnerability has been resolved:
watchdog: sp5100_tco: Fix a memory leak of EFCH MMIO resource
Unlike release_mem_region(), a call to release_resource() does not free the resource, so it has to be freed explicitly to avoid a memory leak.
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Analysis
by VulDB Data Team • 12/01/2025
The vulnerability CVE-2022-50110 represents a memory leak issue within the Linux kernel's watchdog subsystem, specifically affecting the sp5100_tco driver. This flaw resides in the hardware watchdog timer implementation that manages the sp5100_tco device, which is commonly found in server and embedded systems for system monitoring and automatic reboot capabilities when system failures occur. The vulnerability manifests as a resource management error that can lead to gradual memory consumption over time, potentially impacting system stability and performance.
The technical root cause of this vulnerability stems from improper resource deallocation within the driver's resource management functions. The sp5100_tco watchdog driver utilizes memory-mapped I/O (MMIO) resources to communicate with the hardware watchdog timer. When the driver initializes and subsequently releases these resources, it employs the release_resource() function rather than release_mem_region(). While both functions serve to release memory regions, release_resource() does not automatically free the underlying resource structure, unlike release_mem_region() which handles both the memory region release and the resource structure cleanup. This distinction creates a scenario where the resource structure remains allocated in memory even after the driver has completed its operation, leading to a persistent memory leak.
The operational impact of this memory leak can be significant in long-running systems where the watchdog driver is frequently initialized and torn down. As the system operates over extended periods, each occurrence of the resource leak accumulates, gradually consuming available system memory. This memory consumption can eventually lead to system performance degradation, reduced available memory for other processes, and in extreme cases, system instability or potential denial of service conditions. The vulnerability is particularly concerning in server environments where watchdog functionality is critical for system reliability and where systems may run for extended periods without rebooting.
This vulnerability maps to CWE-404, which specifically addresses "Improper Resource Release or Reclamation," and aligns with ATT&CK technique T1490, "Inhibit System Recovery," as the memory leak can contribute to system instability and reduced availability. The flaw demonstrates poor adherence to kernel resource management best practices, where proper cleanup of allocated structures is essential for maintaining system stability. To address this vulnerability, kernel developers must ensure that when release_resource() is used, explicit memory freeing operations are performed on the resource structures to prevent accumulation of unreleased memory. System administrators should ensure their kernels are updated to versions containing the patched driver implementation, and monitoring should be implemented to detect unusual memory consumption patterns that might indicate resource leak issues. The fix requires careful attention to resource management patterns within kernel drivers and proper testing to ensure that all allocated resources are properly reclaimed during driver shutdown operations.