CVE-2022-49481 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
regulator: pfuze100: Fix refcount leak in pfuze_parse_regulators_dt
of_node_get() returns a node with refcount incremented. Calling of_node_put() to drop the reference when not needed anymore.
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Analysis
by VulDB Data Team • 02/26/2025
The vulnerability identified as CVE-2022-49481 represents a memory management issue within the Linux kernel's regulator subsystem, specifically affecting the pfuze100 driver implementation. This flaw manifests as a reference count leak that occurs during device tree parsing operations for power regulator configurations. The vulnerability resides in the pfuze_parse_regulators_dt function which handles the interpretation of device tree nodes for power management components. The root cause stems from improper handling of reference counting mechanisms when processing device tree nodes, creating a scenario where allocated resources remain unreleased despite the code logic indicating they should be freed.
The technical flaw involves the incorrect management of device tree node references through the of_node_get() and of_node_put() API calls. When of_node_get() is invoked, it increments the reference count of a device tree node, ensuring the node remains valid during operations. However, in this particular implementation, the corresponding of_node_put() call that should decrement the reference count and release the node is either missing or improperly positioned in the code flow. This results in a gradual accumulation of unreleased references that consume kernel memory resources over time, potentially leading to memory exhaustion conditions that can impact system stability and performance. The issue aligns with CWE-404, which specifically addresses improper resource management and memory leaks in software systems.
The operational impact of this vulnerability extends beyond simple memory consumption issues, as it can lead to progressive system degradation and potential denial of service conditions within embedded systems that rely heavily on the pfuze100 power management controller. Systems utilizing this regulator driver, particularly those in industrial automation, automotive applications, or embedded computing environments, may experience memory allocation failures that could cause unexpected system behavior or complete system crashes. The vulnerability is particularly concerning in environments where the kernel runs for extended periods without rebooting, as the reference count leak accumulates over time, eventually exhausting available memory resources and potentially affecting critical system functions. This vulnerability directly impacts the reliability and robustness of Linux-based systems that depend on proper memory management practices.
Mitigation strategies for CVE-2022-49481 involve applying the official kernel patch that corrects the reference counting logic in the pfuze100 regulator driver. The fix ensures that every of_node_get() call is properly matched with a corresponding of_node_put() call, maintaining proper reference count balance throughout the device tree parsing process. System administrators should prioritize updating affected kernel versions to patched releases, particularly in production environments where system stability is paramount. Additionally, monitoring for memory consumption patterns and implementing regular system maintenance routines can help detect early signs of resource exhaustion. The fix demonstrates the importance of proper resource management practices in kernel development and aligns with ATT&CK technique T1484 which covers privilege escalation through system resource manipulation. Organizations should also implement comprehensive testing procedures to validate kernel updates and ensure that similar reference counting issues do not exist in other parts of their kernel-based systems.